Afrihost - Cell C LTE speed and intermittent connectivity

Afrihost, as many, including myself, knows is a great ISP with amazing prices, and the service from their call center has always been helpful. However, lately I have had some issues with their Cell C LTE package. Initially speeds were great, and the consistency was on par with the best of them, but after a month(during which I streamed and downloaded a ton of things, the speed dropped, and I started getting intermittent signal. So much so, that I had to start using my cell phone to send emails again. When I called the call center in December, they said I was out of coverage, now please explain to me how I can still connect to the Cell C LTE network if I am "out of coverage".

I think that the issue is that I have been flagged as a heavy user(even though they guaranteed me that this is not the case) and now my line/package is being limited in terms of speed and consistency.