Fuel Deposit Refund!!!!!!

This company says as soon as you return their car they will take at the most 5 working days to re imburse your fuel deposit. I returned the car on 08/06/19 and till today im still waiting on my money bac**** I tried using their online complaints facility but they have no answer for me. I need my money back. Returned the car with a full tank. If only I knew.