Extra 5G that I habe been billed for since upgrade

I did an upgrade on a Samsung S4 Mini ***) that had a free extra 5G and the monthly subscription was R269 per month. When I was approached about the upgrade I opted fro something less which is Huawei at R199 and was happy with this as I have 2 other contracts with Telkom. My discussion with the Call Centre was that I do not want a bill above R800 as I am unemployed. To my surprise I have been billed from December 2015 the amount of about R349 for the extra 5G. I queried this on the 13th Feb 2016 and the case number ***3 is still being investigated even though I received a message on the 24th to say this will be removed and refunded. I still receive the bill with this bill with the extra 5G even after the message I received on the 24th. This evening I have been on the line for more that 40 minutes talking to Nosihle and her Supervisor Thulile who tells me that this is still being investigated and billing has a high workload about this extra 5G so I am not the only customer suffering from this. My fear is that if I don't pay this because I cannot afford I am going to be taken to lawyers and Credit Beaureas with extra payment. I am not going to renew any other contract.