Do not assume your money is lost, contact your payment card issuer at once.

Regardless of debit vs credit, you should always contact the bank and let them tell you if it is possible to get your money back through them. They're in a better position to know because there are a lot of specific details and local regulations.

My answer from this point on is based on the fact you paid with a Maestro card: These things often depend on country-specific regulation, but it appears Maestro does allow chargebacks (refunds) for failed travel providers. Their chargeback guide states on Page 357

Intra-European Message Reason Code 4855—Goods or Services Not Provided

Failed Travel Merchant—Intra-EEA and Domestic European Transactions Only

Chargeback Conditions. For Intra-EEA and domestic European Transactions, when the Cardholder contacted the Issuer claiming a travel service has not, or will not, be provided, and when the merchant is seeking protection from creditors, insolvent, bankrupt or in liquidation, at least one of the following conditions must be met:

1. 
   

   The travel service was covered by a bonding authority or similar scheme according to local law,
   and one of the following:

   
   
   

   – The Cardholder (or traveler) requested reimbursement from the bonding authority or similar scheme and did not receive it, or the claim was declined.

   
   
   

   – For Swedish Domestic Transactions: no additional requirement. The Cardholder (or traveler) is not obligated to request reimbursement from a bonding authority or similar scheme prior to the Issuer raising a chargeback.

   
   
   

   The Cardholder (or traveler) does not need to request reimbursement from the bonding authority
   or similar scheme if the Merchant, bonding authority or similar scheme publicly states that the
   bond is insufficient prior to the chargeback.

   
   



2. The travel service was not covered by a bonding authority or similar scheme according to local
   law, or neither the Issuer nor Cardholder after reasonable effort can determine whether the travel
   service was covered by a bonding authority or similar scheme according to local law.

Basically, it says you should claim from any applicable protection scheme first, but if it is not covered, a chargeback is possible.

You may lose your money, or some of it, if the company goes bankrupt, which seems likely. According to the Guardian, the airline has suggested that credit card customers check with their card issuers to see if a refund is possible, and that package holiday customers may be protected by the package holiday directive. (Neither of these seems to apply to you since a debit card typically provides less protection than a credit card, though this may be different in different countries.) Otherwise, your only recourse is likely to be to file a claim with the bankruptcy administrator or liquidator.

If it comes down to that, the company's assets will be liquidated and the resulting cash will be used to pay off its liabilities. Since the liabilities may exceed the assets, you are unlikely to receive all of your money. Many assets will have been bought with loans (such as airplanes), and they will be used to satisfy the lenders. Only if the asset is worth more than the debts it secures will any additional value be used to pay other debts.

Update: the Guardian article appears largely to have been based on the company's own statement, reproduced here in full. The linked page may change, so it is a good idea to visit it directly, as well as to visit the links at the bottom of the notice, to look for new information.

TRAVEL ALERT

End of Operation of WOW AIR

Information for WOW AIR passengers

WOW AIR has ceased operation. All WOW AIR flights have been cancelled.

How will I reach my destination?

Passengers are advised to check available flights with other airlines.

Some airlines may offer flights at a reduced rate, so-called rescue fares, in light of the circumstances. Information on those airlines will be published, when it becomes available.

What are my rights?

Passengers whose ticket was paid with a credit card are advised to contact their credit card company to check whether a refund of the ticket cost will be issued.
Passengers who bought their ticket from a European travel agent (within the European Economic Area) as a part of a package tour (a package which includes flights and accommodation or other services) are protected by the Package Travel Directive. Those passengers are advised to contact their travel agent to arrange an alternative flight.

Passengers who may have bought travel protection, or those passengers whose credit card terms may include such protection, may be entitled to claim compensation and assistance due to delays or travel disruption. However, such compensation is often limited.

Passengers may also be entitled to compensation from WOW AIR, including in accordance with European regulation on Air Passenger Rights. In case of a bankruptcy, claims should be filed to the administrator / liquidator.

Where can I get up-to-date information?

This announcement will be published and continuously updated on the following websites:

• Icelandic Transport Authority: www.samgongustofa.is / www.icetra.is
  


• Keflavik Airport: www.isavia.is/en
  


• WOW AIR: www.wowair.com
  


• Posted at all relevant airports

General information about passenger rights can be found at www.icetra.is

Information to passengers .pdf

Upplýsingar til farþega .pdf

28.03.2019

In the last case, you probably won't see any money for several months or a few years.

Contact your credit card issuer and dispute the charge, that is to say, request a chargeback. While the investigation runs, that part of your bill will be considered "disputed" and you will not have to pay it. You are extremely likely to be fully refunded.

Oh wait, it's a debit card??? Okay, same deal. Except while the investigation runs, the money will be absent from your account. You are significantly less likely to be fully refunded. The "investigation" could run a month or two.

....and you just discovered one of the biggest vulnerabilities of debit cards as opposed to credit cards.

Normally you should talk to the merchant before doing a chargeback. But you seriously tried... So good enough!

All that said, there's a chance even a chargeback that worked is not a successful dodge. A chargeback only reverses the payment, not the liability. There's tale of some too-clever bankruptcy trustee going after customers who had successful chargebacks, claiming they misused chargeback to make themselves a higher priority creditor than they were, and get paid out of turn. I have my doubts that would stand up in court, but that trustee tried it! A lot of dumb people probably paid him rather than fight.

TL;DR your sole option is to register as a creditor of WOW air with the curator/liquidator of the bankruptcy. _{Unless you bought additional insurance on your ticket}

First off, if you have an (ongoing-) travel insurance ((doorlopende-) reisverzekering), is to call your insurer and ask what they provide for bankruptcy of a travel agent. Usually your bank is also the travel insurance provider in the Netherlands. I'm not optimistic; this SkyScanner article suggests that bankruptcy is not covered in travel insurance, but at least they'll be more knowledgeable on the juridical side of things.

Seeing you paid with a Dutch debit card, which is entirely reasonable when you're Dutch, and have not taken out any additional travel protection insurance (at least, that's what I assume, since you didn't mention it), there's only one way forward as far as I can see: make sure you are a registered creditor when the bankruptcy files (see e.g. this news article). phoog's answer has a collection of official links where the legal curator should be annouced.

You will most likely not be the only Dutch citizen having this problem, so probably someone will create a sort of rights-foundation where you can subscribe, and they will collectively try to get their money back. It means you loose some percentage to advocacy costs, but at least you don't have to go through the legal procedure yourself.

So keep an eye out for the bankruptcy declaration and who the curator is, and contact them, as well as any rights-foundation (belangenbehartigingsstichting in Dutch) which will probably be set up for all duped clients. You might see some of your money back, depending on how bad the financial situation was, but it will take years most likely.

As far as I can see the standard EU safeguard for flight cancellations, lost luggage etc, delays etc does not hold for bankruptcies. You could contact them of course, although I don't expect you to get a refund through there.

The usual 2 week term for sending back online-bought goods does not hold for travel tickets neither alas.

Why most of the other answers are wrong:
You have a Dutch debit card. What the international community here understands from the debit card principle is, as I gather it, some kind of prepaid or Credit Card-Light. Sadly, this is not the case. All the cashback mentions in other answers are, however hopeful, wrong. They simply do not work with a Dutch card. What you did was most likely an iDeal payment (or an actual PIN payment with your card on Schiphol), which transfers your money from your account to the company, in this case WOW air, directly. There's no such thing as a payment company in between, so all the cashback tales you're thrown as a bone here simply do not work. Sorry, but your sole solace is trying to register as a creditor. Please, be my guest, try to contact your bank to get a cashback, but don't be surprised when they look at you weird. It's just not a thing with the Dutch debit card. As gerrit put it:

Terminology note: American "debit cards" are not Dutch "debit cards". In US, CA, UK, "debit cards" typically have a 16-digit number and CVV code, a magnetic stripe, and can be used for card-not-present payments. Dutch or German "debit cards" have no 16 digit number or CVV code, and increasingly often no magnetic stripe either. In US/CA this is often called an "ATM card".

Sorry, but the other answers are from an Anglo-Saxon point of view on the debit card which simply is not true for the Dutch case.