Renault wonder Waters, bad workmanship and assistance.

The worst franchise ever is your branch in Pretoria Wonder waters/wonderboom. At this second(28.09.2019 10:00) im standing next to the road after they serviced my Kwid on Thursday and The mechanic in their workshop did not fit the radiator cap correctly and the car overheated because of all the water sprayed out and this is not the first complaint if had myself with them, now no one can assist me at the branch as they just say they will call me back and theres no one to take my call 10:00 in the morning. I dont know what to do now, with no assistance... Previously i had my roof racks tefitted because they blew off and then again and the after the second time i removed them and now they stand and look nice in my closet, i had this same problem with my brakes took it back 3 times and they did nothing. I am astonished at the workmanship that has gone so bad at this branch.