COVID-19 canceled flight (Norwegian from Spain to Finland), refund request accepted, still not received?

If you paid (part) by card, file a chargeback through your bank for that amount. Attach screenshots of any written correspondence and specify at what date and time you've called Norwegian's customer service. Explain you've been promised a refund (say when) but still haven't got it.

My strong guess is you'll get back the amount paid by card.

I think you should wait. Maybe you get some hits on national newspapers.

As you know, COVID heavily affected air industry, and so they lack of liquidity. For this reason countries tend also to tolerate delays (but usually they requires refund in case of bailout credits): better delay then a bankruptcy.

In any case, in https://europa.eu/youreurope/citizens/travel/passenger-rights/air/index_en.htm#next-steps you have the "further step": after complaining with airline, you can complain to your national aviation authority: you have the list on the previous link.

PS: try to avoid Twitter and Google searches on this topic, or you will get a lot of spam from various "refund claim offices".

The EU hasn't been very helpful on this in the past few months when even fairly reputable airlines like Lufthansa didn't pay back on time (as specified by the law). It's a massive liquidity problem for airlines, and when considering the big picture, the EU executive may prefer to go easy on airlines at the cost of customers (who're loosing non-existential amounts).

You basically have five options:

1. Wait and hope Norwegian pays eventually
2. Chargeback (see other answers here)
3. Sue them, with a lawyer of your choice.
4. If you think Norwegian will go bankrupt before you get your money, chargeback didn't work and you don't want to sue yourself, then you could consider one of the various "Flight Right" legal services. They claim they will help you get the money and as compensation keep 20-30% of whatever you get paid. This is usually bad for you - because in the worst case the company doesn't do anything at, just waits as you would do on your own - but now you loose 30% in case you do get paid. The only time this pays, and I don't think this is hugely likely, is if the company sues on your behalf (or threatens to) - and as a result of that you get paid. You can't force the company to sue, so it's really unlikely to pay off.
5. The legal service option that isn't dodgy: get a company to pay you a lump sum now in exchange for whatever reimbursement you may get based on your flight rights. This is the only option that has full incentive alignment and will result in an economically optimal result. You've got a real benefit: you get your hard cash now, rather than uncertainty in the future. The only company I have found that suggests they consider this option is https://www.flight-refund.com/ (select direct refund). The fact that none of the other companies offer this option suggests that these companies exploit customer ignorance with the scheme outlined under point 4: they claim they sue for you, but in fact they just wait and see, and get 30% without any work of their own. I don't know whether the company I linked to actually offers direct refund - it may be that they just use it as a bait to offer you scheme 4. But you could give it a try. Basic economics suggests you will never get more than (100% - commission) * max_refund ~ 100 EUR, otherwise everyone would choose this option as opposed to commission option. I'd be surprised if they offer more than 50 EUR - but even then - this may be the best option in case you want peace of mind, certainty or are cash-strapped.