So without much info helping is a bit difficult:
What site was it on?
How did you deposit?
How did you (try to) withdrawal?
What did the casino say?
Did you use a bonus?
As I said I had the same thing happen to me and some excuses are:
1. You bank doenst accept payments from casinos
2. Because of Covid we are slower than usual
3. Just wait, it's on its way
4. KYC needs to be done first (even when it was already done)
Although I don't have any real evidence, those casinos always give me the feeling that they want to stagger the withdrawal and hope you reverse and lose all the money. If it's a trusted casino, they will give you the money eventually.