MTN client services

Sometime ago I got a call from someone at MTN asking me if I wanted to upgrade my social data package with my phone and that my payment would go from R239 to R299. This month they did not take the money from my debit order that we set up when I first got the phone. Now they want me to pay exstra because they failed to inform me that my bundle supposedly went up from R239 to R444. I tried to email them and whatsapp them and message them everything to find out why my account payment is so high. But nobody at MTN care services seem to actually care about the matter. I am constantly told a query is logged and they will get back to me but still nothing. I am not happy with the ****ty service I am getting from MTN. Why does it take so long to respond to my emails and just tell my why my payment is so high when I was told that it will only be R299. I am outraged by this and I will not pay if nobody is able to tell my WHY????