Failure to pay back deposit

I took a vehicle from Avis PE Airport on Sunday the 30 June and returned it on the 4th of July. I was told I would get my deposit back within 72hours and today is the 26th I've been sent from pillar to post and no money has been deposited back into my bank account. some tell me it's up to 10 working days others tell me it's up to 30 working days and the person who helped said 72hours. At some point I was told it would be in within 3 days as it was stuck with their bank, now 22 days later nothing has happened infact it's even difficult getting any help from Avis.