R28000 double debit without confirmation

I have been double debuted by avis durban downtown for r28000 without confirmation ,after contacting avis Durban they inform me they will investigate an I will resolve the issue in a few days .i have no money left an I have to take this response as acceptable .this is totally unacceptable ,they have put me in the worst possible situation .i am very disappointed in Avis ,as I opted to use there service over other car rentals as I thought they had there ducks in a row . I hope an pray this gets resolved soon .