It might be that the payment and the mail crossed each other during the weekend.

You can contact customer service, they can check your financial data.

I did call them, and they said that they couldn’t see that the payment arrived to them and that sometimes it takes up to 5 days for the money to arrive, and maybe it would be best if I could send a screenshot of my transfer confirmation. Do you know how many days are needed for money from revolut to abn-amro bank account to be seen?

Transfers within or between major Dutch banks are nowadays done nearly instantly. But a transfer from a Lithuanian bank may indeed take days. It all depends on the procedures of both banks for such transfers (certainly no transfers during the weekend) and in many cases a check will be performed to ensure it's no money laundering. And after the money is transferred NS may take another day to update its own records.

Did you pay with iDeal? Then it should have been received by NS immediately.

I did pay with my Revolut account, not through iDeal but manually like, a regular money transfer. But that’s what I know too, that the money should have been received immediately. The recipient's details are not wrong. I’ve double-checked.  

That's certainly not the case for international transfers. If you transfer money Friday late afternoon or in the evening there will be no actual transfer before Monday because international transfers are not possible within the Eurozone during the weekend (even though your account overview may show that the transaction was executed). And that's even besides delays due to the procedures of the banks involved.

I have done transfers to ABN-AMRO again, and they arrive in a couple of minutes. I’m in contact with an agent via NS chat I’ve sent proof of the transaction but they haven’t reply to me yet 

Yesterday there also has been a disruption at one of the payment processing companies in the Netherlands. Maybe that has delayed your payment.

I hope it was something like that. Still have no reply from the customer service as to what is going on