WORST SERVICE EVER MTN

Hi All I recently was phone by CCI(a part of MTN) to upgrade my contract. After receiving my new phone, I was not happy with it and return it in 7 days. After I contact them I cancelled my upgrade....sins July they did not do anything to cancelled my upgrade contract. They still billing me for the new phone and new upgrade package. After many phone calls, nobody still can still help me..every time "no sir we will come back to you" over and over again..I was **** to over the phone on the day when the man phone me, he promise me there will be no service fees as they are part of MTN.. After receive my first new bill, service fees was added. Promises from there side never happens.. worst service ever from MTN.