MTN inside job took a phone using my account ****SSSSSS

MTN deducted R859 in my bank account and when i call customer service for hours trying to resolve the issue, say someone in Johannesburg MTN store took a phone using my account. To my surprise i have never even been to Johannesburg. The only account i have with MTN is a 2GB router of R139 a month which was coming to its end this month. I was apparently due for an upgrade and they did not tell me instead someone took a phone on 24/11/2017 without my consent......I have not yet received any call or sms from MTN to say they are dealing with this. I want to end any contract with MTN. This is an inside job from this MTN store.