Absolutely nobody knows how to resolve this for me - being sent from pillar to post!!!!

Hi, I am referring to #240433, which was loaded with MTN on 29 April 2019. The problem that I have here is, my contract now has a R316 added onto it, based on a phone call from a sales person at MTN. While I expressly asked the lady are you sure I will only be paying R316 and this is not a top up to my contract, she said yes. Therefore, lying to me, not telling me that it will be added to my contract. Now MTN customer services is saying I have to speak to sales, and sales says I have to speak to customer services, and still NOBODY is resolving my problem. I don't care what the process in MTN is, I just want my problem resolved. The R316 can be credited to my account, and the extra 100 minutes taken back. This is really ridiculous. Easy to take my money, but very difficult to get a problem resolved.