Not paying back the deposit, Even if 12 days passed after delivering the car.

I chose the europcar cause of it is one of the well known in Portugal. But i got that i made a mistake. They said that they will pay back my deposit to my credit card in 48 hours, 12 days passed after i delivered car without problem. I sent mail, i called them, they have very and very poor customer relationship service. It would be my first and last time with Europcar at all.