Can't be trusted

They tried to overcharge my credit card for the deposit. Only when I showed them what I was quoted were they prepared to change it. OR Tambo branch didn't have the car or group I'd booked. Instead they gave me a horrible, smaller car that was terrible to drive. Then after I'd returned the car, I was billed at a higher rate than I'd been quoted and accepted. It's now 5 days later and they still haven't sent me the corrected invoice. When I call they don't answer and when I finally got through their line cut off. Impossible to even get it to ring now. Disgraceful experience!