2 weeks of no network

I am on contract with 8ta and I've been having issues with the network on my phone for the past 2weeks. I've been to their shops seeking help but nothing has been working. They even did a sim swap and I was told to wait 24hours it will be back. 3days later still no network, I haven't received any assistance from 8ta . My calls are put on hold and made to wait for too long.changed phones thinking it was my phone but still can't make calls. And if I do manage to make a call it cuts off mid call. Constantly says no sim inserted. I need to move from this godforsaken network