MTN customer harrassment, inefficiencies and appalling manner.

We have been loyal customers of MTN for many, many years. We upgraded our contracts earlier this year and somehow MTN added services onto our premiums, which we in no way ever signed for or accepted. We paid more monthly into the MTN account, than what our actual contract fees are, yet all of a sudden, some months back, we were cut off and when investigating as to why, we found out that because of these extra services, which we NEVER requested, we "owed" MTN money. We obviously disputed this, our signed contracts were examined by MTN Port Shepstone and obviously it was found that we were correct and that MTN actually OWED US a credit - this was about 6 weeks ago. Depsite this, MTN have since cut us off numerous times as according to them we are behind in payment, and when we call them, they reconnect us and can see on the system that we are due a credit. They reconnect us immediately. This is damaging to our business though, as we don't know how much business we are losing out on, due to not knowing immediately when we are cut off. Today was the final straw where we received a letter from MTN threatening us with legal action if we don't pay an amount of close to R600 and also that they will be handing us over to the credit bureau should we not settle this amount in 20 days. This is now tantamount to harrassment. We have physical proof of the contracts we signed for and, each and every payment made by us to MTN - showing that we have consistently paid more each month than our actual signed for contract fees. Who does MTN think they are by threatening customers when they are simply unable to attend to their accounts efficiently and when the issue is on their side? If this continues we will go into MTN, hand over our devices and cancel our contracts with immediate effect and we will NOT be paying any contract cancellation fees and MTN would be welcome to try and sue us, as we will fight it with all the proof that we have that they are a detriment to our business and harrassing us unduly. At our earliest convenience we will be changing service providers after more than 20 years of being faithful MTN customers - MTN your services are absolutely disgusting and inefficient.