Cancellation

I have an issues with Mtn as they are falling to cancel my home WiFi i returned the WiFi at Mtn store kiosks in Pretoria on the 7th of November as I was going on maternity leave in which the lady that assisted me told me to call 135 to cancel my services since I did my WiFi online and she gave me a IRM number, I left the store and called 135 to request cancellation I was told that my service will be cancelled after 21 working days ever since I have been calling,sending emails and also went to store but still now I have received a statement that I am owing and that my account has been handed over to legal but how when I have been requesting for cancellation I have been taken up and down and still nothing I am also waiting for my refund in which they also told me I need to pay the money they charged me to get my refund