Avis does not refund

Avis is the wrong company to do business with, I booked a car to collect Aug 27th, they did not have the vehicle so transaction was cancelled, I already paid online and refund was promised within 3 to 5 working days, It is Set 20th and no refund was passed as yet, spoke daily to the Branch manager who is no longer taking my calls, also being provided *****ulent and doctored forms as a "proof of payment", as well as screenshots of their internal systems that does not correspond with forms provided, something is very very off there.