Very disappointed with MTN

On 2 June2017, I downgraded my contract for the next two years to data only at R89 per month. I continued to receive bills for R139 per month despite visiting 4Ways Mall MTN on at least 4 occasions. I found the staff to be disinterested and unhelpful. They assured me they had notified MTN and that within a month or so I would be credited for any overpayments I had made and my bill would be corrected. In December I was billed R95 instead of R89. This I paid. In January, February and March I have received warnings that my service will be suspended if I do not pay MTN R147.95 per month. I have paid all these amounts which is almost double to what I was advised. This is disgraceful especially due to the fact I am a pensioner and need to be very careful with my budget. I sent an email to MTN complaints where I asked for an urgent reply to my query. I have not heard from them at all. So very disappointed with this service. I will also be posting this complaint on Facebook for those who do not regularly visit hellopeter as I am sure many people have the same problem