Terrible customer service, not honoring 3 months free contract upgrade.

In June I upgraded to a contract which clearly stated that 3 months is free. Not only was I charged for those 3 months, but they also kept charging me for my old contract. The last part I can let go of, but the 3 free months I can not. I have logged tickets telephonically, via email and via social media platforms (publicly and privately). I keep getting the same generic answer: "It has been escalated to the billing department, we will provide feedback soon". No feedback for 2+ months. I keep following up and never receive feedback.

I have been a loyal MTN customer for years, but this is simply beyond ridiculous! It seems quite simple, refund me the 3 months and we're all good.