Thrifty won't return my money

Absolutely shocking service. Firstly, you get treated like a ******** for owning a debit card instead of a credit card, even worse if you are a first time renter. I returned my car on the 4th of March and still have not received my deposit on the 16th of March. When I call customer service, they tell me it's been paid on their side of the system. When I assured them that this was NOT the case they got back to me and said there was an error in the system and they see that I was not, in fact paid back. I must now wait a further 1- 3 days. The amount taken from my account is more than I earn in a month and I have been left penniless for two weeks. Absolutely unacceptable.