Bad client service at Dollar Thrifty Johannesburg

I frequently hire vehicles from Dollar Thrifty in the Johannesburg area. But their damage report system is and client feedback is ridiculous. After taking the extra cover for the "Peace of mind" that is advertised for tyre and windscreen cover, I get charged ridiculous amounts for a small stone chip on the windscreen. Where is the "peace of mind" offered? Once I got double charged for a vehicle hire and its taking months to get a refund, not only that, I did report it and got an email to say matter is resolved and closed but no one informed me nor did I get my refund. Ridiculous service and system, very very disappointed