Terrible Service Excessive Charge for Data

I contacted MTN on the 5th May regarding data usage on my account and related charges. I have not received a response to date, 21st May. I have had to contact them for updates on my case and have been advised on 2 separate occasions that the case was forwarded to the relevant department, on the second I was advised that the first person I spoke to did not forward the case, **** to me or is ***********. I was promised that the issue would be addressed before the invoice for May was finalized 14th May, this did not happen, I was then advised it would be addressed before 20th May (debit order date), this has not happened. My complaint is related to Data Bundles, Promo Bundles and the text messages I do not receive any more with Data Bundle usage information. Last month I was billed approximately R 900 for 40 Gigabytes of Data, this month I have been billed R 2500 for 42 Gigabytes of data. This does not make sense, this is not acceptable, an explanation was requested but none provided. I am appalled by MTN's service, I expect an explanation and or re mediation before MTN can expect payment! Please stop lying to me and do as you have agreed to!