Incorrect billing, I want a refund

Where do I begin… let me pull my hair out first! I battled for the longest time in 2016 to figure out why MTN was billing me x3 more than my monthly amount. I eventually got told that I had activated a data bundle self-service option on my account and for that reason I was being billed this ridiculous amount. I tried to explain to MTN that I didn’t activate this nonsensical option, all I had done was to buy myself airtime and data from my FNB mobile app (mind you with my own money). I was told that I shouldn’t have done that because that’s exactly the reason why the self-service option was activated & MTN was charging me over R1 500 for data I had bought for R160! Eventually on Nov 5, 2016 I got told by an MTN agent that she can’t cancel this option for me on their system, I had to do it myself by dialling *141*5#. I then cancelled all 47 options. It took me hrs but I did it in hope that MTN will stop billing me these ridiculous amounts! Well I was seriously mistaken. MTN continued to bill me in Dec & again in Jan 2017. I called MTN on 26 Jan to query these billings. At 1st the agent couldn’t see my cancellation for the self-service option but then he double checked & confirmed that he can see my cancelled of Nov 2016 & would escalate the billing query, ref no for the call was ********** 47, SLA 7 working days. When I followed up on 9 Feb I got told that systems were off, ref no. REQ ********** . On 14 Feb I followed up and this time I was told that the feedback received from billing was that I had cancelled the self-service option only on 26 Jan and that’s the reason why I got billed in Dec & Jan. I then asked call centre to have 1 of the managers listen to the telephone recording of the 26 Jan where the agent confirmed that he can see my cancellation of Nov! My last reference of 31 March is ********** 93 & sadly I’m still waiting for feedback! I give up MTN, you have seriously broken my spirit!