Telkom is spoiling my account and my credit records

Telkom is more like a ****e to me. One of its agent sold me a phone telephonically, saying is the latest when it arrived it was the earleast. I called them they say I must return it back, even though they got thier phone they keep on deducting my money since november last year and the money is more than the one I agreed before I saw the phone. According to our agreement it was gona beR99 pm bt now Im talking about R623, it increase monthly. In all Telkom re is benefiting twice because their phone is with them and also my money. I traid last month to call that agent they told me that they are only selling phone is telkom whose dealing with deduction. I hate telkom