billed for phone not received

A debit order of R619 owent off my account,then I went to mtn store to enquire about it then the lady told me I upgraded my contract from 59 to R1000. Which did not make sense to me as I have not gone to no store to upgrade. So I was told to call 808 were I spoke to (lerato mohale) who said she will cancel it. But never received any communication of such a contract too much ***** with these cell phone companies as same thing happened with Vodacom where ended blacklisted for a phone I did not receive. I want this cancelled immediately and I am going to reverse the debit order. These companies keep affecting accounts of unsuspecting clients so sales consultants to make commission