Charging for extra days when I didn't have car

Rented a car or tambo and returned it on 9th October but the invoice says 13th now they want to charge me for the extra days their phone lines only rings nobody picks up. I will get my bank to reverse the charge. Bad company bad experience this is ***** for charging for services not consumed and we have a boarding pass proving that we left Johannesburg that day. Will never use them again I will rather pay a bit more for a bon error company that just charges you for more days with no proof