Internet is at dial-up speed for a 4 MPS line

I have been calling Telkom for months now trying to get my line sorted. I pay for a 4 MPS internet speed line. What I'm getting is 0.5 MPS download, and 0.03 upload speed. They will give me a fault number, then a few days later, with nothing done, they send an SMS that the fault has been fixed and closed. Then I call back and tell them it hasn't been fixed but they insist on opening another fault, then they will randomly close it without ever fixing it. I've spoken with managers who tell me they'll call back which they never do. I have escalated it and still no help. That's the problem when you have a monopoly in the country. They aren't accountable for service.