Ongoing Problem with MRPMobile

I wrote a report some months back about this incident, please refer to previous report re tablet for earlier complaint as this is connected. After my report MRPmobile got back to me, apologised profusely and we came to an agreement that I would no longer be debited and that I would pay for the courier to collect said tablet from me and return to MRP. Since I had already paid something to MRP they subtracted that amount from what I owed for a courier and I was just to pay the difference which I did immediately. The lady I was dealing with said my debit order would immediately be cancelled. The tab was collected and returned to MrP, but at the end of November the same debit order of R128 went through again. I immediately phoned MRP and I spoke to a gentleman who said that he cancelled the debit order while we spoke and that the R128 would be credited to my account only in December. Instead today my account was debited once again by MRP, but now for an amount of R529. What must I do to get this sorted out, they are just the most useless business I have ever dealt with, dishonest, ******** and con artists, totally inefficient! They should be named and shamed and taken to court.