Disgusting Service from MTN SA

To get service from MTN is mission to the moon and back, you have to be a rocket scientist..... MTN advertised a black Friday deal R799.00 which will expire on the 7 January 2021, Unlimited minutes and 60G of data, I then called in on the 11 December 2020 as asked the sales rep to give me the deal which he did, how ever at the end of December 2020, however to my surprise I was charged incorrectly, I then called the customer services and was advised they transfer me to sales dept , I spoke to the rep but was told to speak to customer services ( REF number***), this was on going for the past 7 calls to MTN from department to department and no one ones to take the ownership, so my understanding for this service is ..... MTN so too big now to look after their clients to has contributed over 10 years , a business which is now worth $255 billion dollar business , well its seems like you guys are just to big now to worry about a drop in the ocean, MTN kindly advise me if you need my business kindly give me the aftersales service that I deserve or if not then iam willing to go to your competitors. PS MTN I have a record of all my transaction that transpired thus far. A very disappointed customer