Don’t use Avis they don’t refund your deposit back

I have returned my vehicle to the airport a month ago and I have not received my deposit back I called in two weeks ago and was told the refund was processed. I have tried numerous times to call the callcentre, sent emails, chatted with Facebook and no response a month later. There are numerous people having the same issue with Avis if my money does not get refunded I will be taking this further