DEPOSIT NOT RETURNED

We hired a car from Hertz Mauritius on 25 April 2019 from Victoria Beachcomber- for 1 day. Car was returned and as per Employee at Hertz the refund was processed. She cannot give me any proof that this was done. To this date I have yet to receive my deposit back. My bank locally cannot pick up anything and require proof of the return. I do not feel it is fair that Hertz is earning interest on my money.