I can take a guess (something involving magic wands and toadstools) but I would be wrong. I reckon that the problem you have is something that needs to be addressed by Telkom - either your line is not so great, or your modem is not so great, or the quality of the link from your area to Telkom's distribution point is not so great. Maybe you have a really busy device on your network that is sucking up all your bandwidth? If that's the case, neither Telkom nor Afrihost will be able to help you: you will need to find that thing yourself.
If Afrihost is not responding, it's probably because they're not getting your message.