I'm having a similar but slightly different issue. I have a 6 meg business package on a 10 meg line. I'm able to torrent at a very stable 700 kB/s, with speeds going as high as 1 mB/s, if I unlimit it. Voip always works perfectly, and I can generally connect to games without issue, provided utorrent is closed.
My browsing experience is however atrocious. Browsing is severely impaired no matter how low I limit torrent speeds to, and while it improves when I close the program completely, websites still constantly time out even when it's closed.
I have a rainmeter extension that constantly pings a amsterdam based game server, but it mostly just returns the 30k ms time out result.
This has been going on for several weeks, with the severity of the issue varying. Some days I can't load a single page. I spoke to a Afrihost call centre person 3 weeks ago and he gave me another afrihost account to test with, but the results were the same. I also spoke to Telkom, and was told that somebody from another department would call me, which of course they never did. I was on hold for 35 mins to get through to Telkom, and 25 mins to Afrihost, so I'm not trying that again.
I thought it might have had something to do with this
http://mybroadband.co.za/news/adsl/122012-adsl-problems-caused-by-new-telkom-system-isps.html
Anyone have advice/ideas?