Cancellation

I purchase a device by for R269 month for 24 months. They aldo inform me if i m noy happy i can returm with in days. So i wasnt happy . I return it in January already but thry still deduct grom my bank account and hand me over to a collection agency now. It almost 7 month now and it still shows on my credit report and due to this i can't even get a house. I never use their data and i return it to one of their branches which is century city in cape town the refence number is SR*** and the lady at Mondi which name is Asiphe told me that the ine at MTn who is still busy with my cancellation is Rudzani Mukhubha. The query as had escalated since February and never been resolved and its so frustrating.