Mtn slow assistance

mtn used to be one of the best people to do business with until now. I have been asking them to cancel my contract from june and no assistance called their customer service line and they say i must go to store, i go to the store they say call cistomer service. Recently emailed complaints they have not gotten back to me yet on my cancelation, mind i am still paying for the phone that i no longer have with me i didn't even opened the phone. Its ridiculous and I'm tired of it their service was excellent now its horrible.