None payment of withheld deposit

When renting a vehicle from Avis, its a standard procedure to withhold and x amount from the customer; after drop off the x amount is released and paid out in 7-10 days.

I rented a vehicle on 4 & 5 May 2019, and still no release of the 'deposit which is due to me.

I followed up last week Wed and was told that I should check my account in 24 - 48 hours for payment made, I followed up on Friday and still no feedback and no response.

This is terrible service. The system here is flawed and this is *****.