nobody seems to know what they are doing at MTN South Africa

I have made a upgrade on the 2 of September 2023 AT MTN Karaglen assisted by the lady called Lebogang , our agreement was that Im going to start paying R699 for the new device in November 2023 but I got a surprise when they debit me R1198.73(FOR 2 DEVICES ) in September ,R1095.01 in October and R947 in November and I tried to complain at the lady who was assisting me she seemed not to care or even come back to me and explain was could be the problem. I also tried to call the call centre no one could explain to me what could be the problem and they end up hanging up on me . i regret doing an upgrade with MTN and I will not recommend MTN even to my worse enemies.You are treating your customers unfairly and you must stop calling us to come and make upgrades if this is how you treat your customers. i need my money to be refunded before end of December or im gonna Escalate this matter to the right people maybe by doing so I will get help because no one seem to know what they are doing at MTN.