Overcharged on my MTN contact bill for Data purchase that was supposed to have been cancelled

MTN Keeps on over debiting my contact account. I purchased data once via the MTN menu and when I got my bill it was more then expected. i paid for it the first month. afterwards I contacted the call center to have them remove that option so it doesnt happen again. second month over debited again. I contacted & spoke to numerous consultants... Nosipho, Sifiso, Rosha without any help they told me the manager by the name of Veshain Vasram will contact me with Ref: ********** 12. he was going to listen to the voice recordings he still getting back to me. when I called in I was placed on hold for over 15minutes till the call got dropped.