MTN *****ing money from my account and not rectifying the problem

In May I added my husband to my contract and I upgraded. He took a package that only includes minutes and no phone. We were charged a large amount, but I understood the pro rata thing. But then I found out that they are billing me almost double to what I agreed on. After going into mtn and phoning numerous times, the issue on my cellphone was sorted and they gave me a credit. But still my husbands problem persists. I have been into the store so many times, phoned uncountable times, e-mailed etc and still nothing. His contract is suppose to be R499 a month, but first they charged him R886.23 and then after a few months that changed to R711.53 which is still not the R499 we agreed on. Every single week they tell me it will take 3 working days to fix and I should call again and then I call again just to hear that the problem still isn't fixed. They show a credit on my statement, saying that that is for my husbands problem, but still they deducted over a R1000 this month again. Last month I reversed the payment at the bank (as the manager at our mtn branch told me to do) and only payed what I agreed upon an now things are even worst as they deducted even more money and that after I payed via eft. On the statement where they say I have credit, they deducted my payment from that showing that I owe them R375, but in fact they owe me almost R3000 now. I AM FED UP!!! Mtn is *****ing my money, as I did NOT agree to this and you are not fixing the problem. In my eyes this is *****. Every week I get empty promises of it getting fixed and then you just deduct more and more money. My contract is only suppose to be R720.18 (for both numbers) per month, but you far exceed that and by taking more than that from my account is *****ing. I want this sorted ASAP!!! I want my credit payed back into my bank account ASAP. I want the monthly installment for my husbands number to be corrected to R499 per month ASAP. I have been struggling since June 2018 and if this isn't sorted out ASAP I will be contacting the ombudsman.