Mtn bad service

On the 22nd of August i was fooled by an mtn made for home data advert on tv ,and that is when I decided to call their retention center asking for an early upgrade because i was suppose to upgrade on the 6th of September ,they agreed and helped me . The package was a router and monthly of 15 gig night data and 20 gig daily as advertised and it was suppose to worth R369 monthly but on the 31 of August they took R422.67 and i said to myself maybe its just the upgrading charges since i was left with few days before my due date, on the 31 September they debited R423,67 and i kept quiet hoping this might be the last time but on the 31 of October they debited R910,90 and because of that my other debit order bounced ,leaving me with arrears .i called them on the 31 ref no was 1- ********** 4866 and they promised to resolve my matter and return my money ,but on the 2nd November my money wasn’t returned and I decided to go their store in burgersfort ,they opened my account and found that i was paying for an extra 5 gig which I didn’t sign up to , the reason they debited R422,67 and R423,67 but as for the R910,10 they ddnt have explanation for it,they told me there is nothing they can do since i upgraded online, they called them and let me speak to them , I stayed on the line for more than an hour with their consultants playing the tranferring to the right department game , end up with three references numbers on one call ( ********** 28, ********** 40, ********** 27)with no help and no explanation .to cut the story short, i then decide to go to the bank and reverse my money ,that is when they respond with *********ing emails, and i explained my story they said they were sorry they will attend to case but nothing till to date but an invoice of R1597,66 which I cannot pay and im willing to go and block them before then because I cannot pay for something I don’t understand , so please be careful with mtn,so frustrated and disappointed