Avis refund

Hi..I hired a car on the 19th November and returned it on the 27th of November 2018. today its the third week since i haven''t got my refund back , when i called the Vincent offices in East London they told me to wait. When i called the Head Office the last week Friday the lad that I was talking told me that they were going to call the bank to release my money it takes only 48hours, but since today the money is not in my account. I dont not know now what to do because Avis has been regarded as the proffessinoal company which refunds people within 7 days.