Is the phone ****** from your staff member ??

I took a contract phone with MTN July 2018 ,they delivered a wrong colour and I took back the phone on the 17August 2018 to mall of the south within 7days , never switched it on nor use it but they are debting from my account every month for something I don’t have with me, got assisted by a guy by the name of Tshepo Mogano on the 17 of Aug 2018 but he wouldn’t give me the correct tracking number , no one knows where the phone is , all he says to me is that it’s at warehouse with A guy by the name of Tereence Maposa “the manager” this is really frustrating because every month I must pay something that’s not with me and I must revise the money and get charged extra fees for revising even after I had told them to cancel the check contract because from my side I can’t because I don’t have the tracking number that was suppose to be given to me from the day I returned the phone, I am extremely annoyed at the service I’m getting from Mtn ,this is affecting my credit score as I constantly have to revise the amount of this phone I don’t even have