Overbilling and Delayed Responses

I was overbilled by Telkom (pro-rata charges) and logged a case since November 1st, but till now, it has NOT been resolved. On the 31st October 2017, I upgraded my contract with an iPhone 6s deal (R399) with Telkom, and I clearly asked the call-centre agent if I‘d be charged for a device since it was already the last day of the month. She said “NO” as can be heard in the voice recordings. The November Invoice came reflecting a device fee and spend limit put in place without my concern. I called and requested this to be resolved to my expectations and stated that if not, I need the contract canceled before the “COOLING-OFF” period ends. I called a few days after and fortunately found the case closed but with remarks saying “THE SALES AGENT SHOULD HAVE EXPLAINED THIS TO THE CLIENT” of which not saying what the resolution was. I opened another case as a follow up to this, still no feedback. Every time I call in, I get response “YOUR CASE IS STILL WITH THE BACK-OFFICE, THERE’S NOTHING WE CAN DO EXCEPT TO ESCALATE THE MATTER” from the call centre people. In December, I decided t o call my bank and reverse the excess amount that was charged but they could reverse the entire debited amount. Again, in January, they overbilled me but let that one slide as I didn’t want to reverse all the debit orders. If anyone can help, my case numbers are [( ********** 3, ********** 6, and ********** 7].