Vox Unable to fix Uncapped package running out of data

My husband and I have had numerous telephonic calls to sort this out but unfortunately had no luck in getting it fixed. We are currently subscribed to your NeoBroadband Wireless Uncapped, Acc No. ***. With Neotel pulling out of this space your technicians replaced our existing installation with a new LTE Huawei router and MTN sim card. Everything worked great until we started receiving an "Out of Data" message when connecting. Obviously, this should not happen with uncapped. We have had numerous calls to Vox, whereby the temporarily load data, or close our Vox tickets due to the sales person suggesting Fibre installation, in a area where there is no Fibre available. I need this running "Out of Data" issue to stop. We are paying a lot of money, to have NeoBroadband Wireless uncapped.