Cancelation Issue

Good day, i am utmost disappointed in MTN, I have been a client for more then 15 years, I have faced numerous challenges with them. I cancelled a home internet Solutions 4 Months ago. I followed the procedures, took the router back to the store, filled and signed all forms requested. The router was then collected and all references were logged for cancelation, the consultant that assisted me advised that the cancelation was rejected and that I should call in. i have been calling in ever since with no luck. I need this solution to be called with immediate effect as well as get credit for the past 4 Months and my once off payment to be cancelled.