Mtn - Cant upgrade or cancel

Dear MTN writing this is not where I wanted to end up as I do like your brand and service in general. However In the run up to my contracts end date I have tried to upgrade my Sim only contract online. The credit check is a problem due to debt review. It gets provisionally accepted however I never hear anything back from the online department and when I contact them it goes nowhere fast after a long wait. on the 19th October I emailed retentions with a request for assistance with either the upgrade to a sim only which incidentally is the same price or at the time was R50 less a month, to which I have had no response. again this morning I have attempted to phone 135 to cancel only to be cut off after 50minutes on hold. I am not trying to take out a device only a sim only deal which is a service agreement. I want to either sort out a new sim only deal or have my data bundles removed from my account to avoid excessive billing going forward.