Telkom LTE Dead in the water

So, for the last few months, my Telkom LTE has been more or less unusable. This is a common theme in East London and specifically Cambridge. The service is advertised as "Up to 90Mbps - Average 10-20Mbps" but is performing consistently at 0.5Mbps - 2Mbps which is nowhere near what it should be.

Telkom has not responded appropriately - the only contact I've had basically boiled down to "It sucks to be you".