Even cancelling your contract is a problem

Problems have persisted throughout my 3 contracts with vodacom and even now with my last ones cancellation there is a problem. *** was cancelled in December 2015, realising vodacom never do their work i checked in January and lo and behold it was not cancelled i then sent an email requesting cancellation and received a letter back. Now 11/02 i receive a statement saying i owe R140, contract was R154, so this number was not cancelled and i get billed for their mistake of not cancelling the contract in December. Please block this number before i hear vodacom again. I will be stopping the stop order and blacklist me and we will see each other in court