I've just replying to this for the last hour - time out after time out :/
Basically, I have two Blackberrys : a BB9700 (OS5) and BB9800 (OS6).
I have a 32k, 64k and 128k SIM card.
I have 3 modems (E220, K3565 Rev 2 and Acer 7.2) using 3 different software (VC Lite, Mobile Partner and Globe Trotter)
I'm trying on 2 machines running WIn XP and Win 7.
Each gave the same error and I'm doubting everything can be wrong. I've also needed to get myself a Telkom SIM recently and it always works.
It's not only with BIS - it's their data as well. 70% of the time on GPRS (timing out, taking 5 minute to load any page etc), 20% on 3G and the remainder GSM or simply offline. It's at the point that when I pick up my phone, I'm actually doubting it's going to work. Had signal or the network been poor in my area from day 1, then I'd blame myself for signing up knowing that they network is terrible.
However, on the data side I'd get 140ms pings and 2mbps downloads a year back. The past 8 months? 240+ pings and 600kbps if I'm lucky. The entire morning I haven't seem a 3G signal on any device and even this post took about 5 or 6 attemps.
I'd never be throttled at the amount I can download anyway

It took me about an hour to get Facebook 1.9 (1.4MB) last night.