Hah, I thought I recognized the nick - last month we were in the exact same boat. Eventually my connection got so slow I couldnt browse here, and two weeks of Telkom telling me the line is fine, ISPs telling me the accounts are fine... and bam it started working again. Fast for the last week and a bit of May, fast for the first week of June. Then suddenly the last few days its been getting slower. Now it's maxing at about 15k/s for http files over 200k, large files mostly under 5k.
I'm pretty sure there's some strange connection between these 1mb issues.
Edit:
I have pretty much exactly the same speedtest numbers, but in reality the numbers are way lower on normal servers. I'd link the image, but it keeps telling me its 0.png :/ 51k down, 43k up. My up speed is always max, but down... oh lawd.