Slowest internet speeds ever!

I recently joined Vox after a 3-4 year nightmare with my previous service provider. About a month and a half after joining Vox, I experienced very slow internet speeds, 0.1mbps up to 3mbps on LTE which used to be 20mbps+ sometimes up to 60mbps!

I sent them an email on 22 November asking for assistance. Although they contact me and tell me they're working on it, it's been over 2 weeks with absolutely no change! They also keep promising that someone will contact me so that we may figure this out but the days just keep passing without anyone offering a solution.

I understand that Telkom LTE has been contacted and will look at their tower or whatever, but this only means I'll probable wait months for a result, and I'll have to keep paying for a service I am not receiving. So far I have spent more money on additional data on my MTN contract than I pay Vox monthly. I work from home which is why fast internet is crucial. I definitely won't be refunded!

Typing this report, I have had to switch off the wifi and is tethering from my phone.