MTN Hyde Park branch totally useless.

MTN at Hyde Park Centre is appalling. I have had my current MTN number for decades. Suddenly my phone can't receive landline calls. MTN investigated, made an adjustment which lasted for a day or two and the problem recurred. Their records show the number has been re-consigned. This was done by them, but they don't know why and they don't know how to fix it. So the problem persists. They are unable to unravel this mess. I cannot change my number as I use it for personal and business. Competence and customer service are an alien concept to them.