Rude and unprofessional service from Motorland East London

I brought my mother's vehicle for service last Monday 19/8/19 to Motorland East London. I drove the car from Keiskammahoek to their premises and informed them that it had a problem, you have to wait until it cools down for it to start again. I paid R3162 for its service and when I came to fetch it in the afternoon, it doesn't drive beyond 20kmph, they messed it up. I drove like a chameleon sending it back in Tuesday, was ignored for a while but was attended by two rude employees and another employee intervened and I was told to leave the car and I did. Friday afternoon, I am told by their principal that they do not know what is wrong with the car but I must pay R6440 for it because they have disassembled it and still need to assemble it and will not release it until we PAY. The car is a Ssangyong Korando, we took the car to them as Google recommended them. They messed the car while it was brought for service