Poor, slow services with no feedback!

My Straight Up 400 contract can been ready for an upgrade for 6 weeks. When I received my initial upgrade notification sms I attempted to process my upgrade. There were some issues and Cell C were unable to upgrade my contract at that time, or at all from them - six weeks ago. They don't return my calls and have not made any progress on my issues, which all apear to be related to Cell C structures and systems. Mean while I just keep paying. I've pleaded for assistance and still get the same we'll have a look and get back to you! I've even been told to consider another network! Service delivery is shocking!