Poor quality and poor service

On 2 September I received my new cellular phone and I purchased a cover for it which was R780. About a week later when someone was looking at my phone they noted that the plastic clips on the cover was cracked and busy coming apart. Since I did not drop my phone I found this surprising. I took the cover back to the MTN shop and was told MTN cannot exchange it, they would have to contact the manufacturer of the cover. They took pictures and promised me someone would contact me the next Monday. It is now 2 weeks later and no one has contacted me. The plastic clips are now completely broken - just from every day use of the phone. For R780 i expected the cover to at least last more than 4 weeks! And I expect to be called.