MTN not to be trusted

I reported my problem of MTN overcharging me for 4 months as they did not do my upgrade. They told me they will pay me back in 7 days after I provided them with my contract. The money is not reflecting today in my account. I phoned to follow up and now I hear they have put it into my mtn account. this is crazy. they take money ********ly then keep it. I want them to be fined my money paid back with interest all al the debit orders that did not go through because of them to be paid as well. we all work on budget but they can take R8000 from me for nothing and then try and keep it. They will probably cone back and tell me again it will tale 7 days. How can you trust a company like this.