Delays in payment of deposit refund

I hired a car from Budget from the 03 of February 2020. The car was returned on the 10 of February 2020 as per the agreement. Since then I've been waiting for Avis to release my deposit, I've been calling them wasting my airtime with no feedback from Avis. I dont know what to do anymore to get my money. I am very disappointed to me after you return Avis car they dont car what happens to the customers. A big company like Avis you will expect that they have an automated system in place. When I called them no effort was done to pay my refund, I was like I was reminding them that I returned their car and they must release my deposit.