Worst experience and service ever

Worst service ever would not recommend it to anyone ...Called mrp mobile last year and told them we wanted to "settle"the contract and close it off and they sent settlement letter and mentioned nothing about a cancellation fee at the time and they said its payable within 7 days .My understanding is that if you want to settle an account they need to put everything that you owe them ,if they had mentioned that in the beginning I would have not had a problem nothing at all however after months of settling the account they call and say I am owing them so the R1000 odd amount we paid they kept debiting it for monthly instalmnt and said nothing about it..I have been recieving numerous calls harrasing me and spoke to different people even managers and was at some point promised that it will be closed they see the mistake however till today I am getting calls of outstanding balance which is annoying the life out of me .