Poor service

My little sister went to DStv maponya mall today because our decoder isn't working. She had all the cables we got with the decoder so that they would check all sources of the problem. They took just the decoder from her and plugged it in using their own cables and told her its working and sent her on her way without trying to figure why it was working on their side while it wasn't working on our side. Instead she was told that the problem was with either our TV or our dish.

Mind you they didn't even bother looking to see if there might be other problems. When I got home from work I tried plugging it in and it still wasn't working. I went to borrow that black plug that the decoder comes with and it worked which means that the plug was the problem and they would have figured that out had they done their jobs. I had to do their job for them. As I'm writing this I have no access to TV right now. I'm so ****ed with the service my sister got because she's younger. Something needs to be done. The ladies who were supposed to help us failed us.