Inefficient, unhelpful, arrogant client service at MTN stores, call centre

I took out a 24 month cellphone contract with MTN in Feb 2021. The contract, which included a cellphone device, was to pay R279 pm for 24 months. There was no problem with this agreement, until I got a call from one of their MTN call agenst on 1 Dec 2021. She promised to reduce my repayments from R279 to R249 pm. This sounded like a brilliant idea, and I was happy with this offer. This was, however, tbe beginning of my nightmares with MTN. Instead of reducing my repayments, I noticed that my debit order was in fact INCREASED. Since Jan 2021, I have spoken to, at least over, 2 dozen MTN call agents, consultants, credit people. ALL OF THEM ARE REALLY USELESS. They make EMPTY promises to investigate this matter and sort it out, TO NO AVAIL. They are just a bunch of ***********, ineffective, unreliable, arrogant people. I have also tried to sort this matter out with their Newmarket, Alberton store. Wow, here again, I met some arrogance and referred to their call centre. Their CALL centre; (083 135/083 1 808) is one of the worst, disorganized entity I have ever dealt with. VERY PAINFUL, UNHELPFUL!! This MTN inefficiency is affecting my credit score, despite the fact that I have stuck to my side of the agreement of paying the R249pm, as agreed in Dec 2021 with their agent. All I want is MTN to rectify this mess and restate my account to the correct agreement.