Asking for a paid- up letter and cancellation

I am deeply disappointed by the treatment I received from Vodacom,after I wrote to you about paying Vodacom all the money that I owed them,I asked for my contract to be terminated and give me a paid up letter so that I can produce for application for my sons NSFAS, they said they don't issue paid-up letter,after I wrote to u their consultant called me and asked for the proof of payment,I said I have it,she then said she is going to send me an email where I must send it, till today they didn't send any email,the following day they called ,I gave them all the information they needed,the consultant told me I owed the more money whilst I paid them every cent I owed them,my son did not go to school because I didn't get this paid-up letter