CANCELLING A MTN CONTRACT - GOOD LUCK!

I have two cell phone contracts with MTN and overdue for an upgrade, but I would like to cancel and migrate to prepaid. I visited my local MTN store in Newton Park to cancel my contracts, just to be told I can only do it by calling 135. Unfortunately, that is where the problem starts - I cannot get through to speak to a consultant when calling 135. I do have the MTN app on my cell, but guess what, you cannot do any cancellations on the app - you can only call 135 (MTN Retentions Department). How difficult can it be to cancel a contract with a "Mobile telecommunication company"! It makes you wonder...