Upgrade nightmare

I received a phone call from SellDirect in April 2018, stating that they are from Telkom and that my 5GB data contract is due for an upgrade. I was offered a mobile wifi router and 10GB for the price of R139 monthly. I accepted this offer. Took delivery of the device and sim a week later. Sim card was activated a few days after. However, the monthly data was not upgraded to 10GB. I still only get 5GB a month. I sent several emails and made several phone calls to both SellDirect and Telkom. SellDirect confirmed that they gave the correct instruction to Telkom and the deal code on their system is the same as the deal code on Telkom's system. Deal code: CCI ********** . HUAWEI E5573 LTE MIFI ROUTER RET +10GB TM Data on Smart OneRate @ R139. Forwarded this confirmation to Telkom. Telkom agent advised that she could not access my account at that time and will get back to me later. This was on 6 June 2018. It is now 12 June 2018 and I still have not heard from her again.