Builders warehouse nelspruit bad service

Good day I've purchased an aircon that was on promotion for R6999 an 12000btu goldair and so they bord says ask for assistance on installation so i did and they organised a guy from their side to come and do it 3 months later the aircon is not making cold anymore pipes are freezing up on the outside but nothing on the inside phoned the guy who did the installation he came out said he did fix it 3 days later same problem again i don't want the aircon anymore as it was a **** buy giving problems in the first 3 months and that kind of money you don't pick up on the street paid the guy R1550 for the installation and now if you phone him he doesn't answer the phone bought the aircon from builders mbombela **** service i received from them the guy who arranged everything and working at builders name is ethran now im sitting with a 3 months old aircon that is not working and summer is on us im not going to pay an single cent for someone else to come and fix it or take it out and replace with a new one im not going to pay installation cost again i want this problem solved from builders side as it is their employees and connections who does the installation and as they advertise ask for assistance on installation