Unacceptable delay

I rented a car from Bidvest 2 weeks ago i retured it on the 6th of February on time filled it up FULL at cape town international, only to find them debiting my cheque account days later as the car wasnt FULL enough which is impossible as the petrol attendant told me its filled to the brim. Not to mention the R5500 security deposit is still not refunded back to me its been over a week now its a crazy amount of money considering the rental fee its almost 8k to rent a car these days, its ridiculous and unacceptable there needs to be a shorter delay in the refund on cheque cards no one has that kind of money these days to just wait upon and no one can tell me when my money will be refunded. Never again its not worth this insane hassle