I was having an issue trying to sign online on several IMs. Not mention I was getting a "Browser WAP 2.0" error as well. I was running on the 4.5 OS from RIM and not the old 4.2 from T-mobile's website. T-mobile then recomended me to downgrade my software to the 4.2 which they support. After doing so, I lost all my address book contacts and I kept on getting the same error "Service Not Enable".
After 4 days arguing back and forth with T-mobile and Rim. Finally T-mobile comes out with a document stating, they do NOT support Windows Live & Aim messengers for the BB Pearl 8100s, only Yahoo IM. RIM said for these programs to work, T-mobile will need to send your service books from each IMs. For that case, when you try to sign in, you will keep on getting error "Service Not Enable For This Handheld".
This is pretty stupid because my main reason to use the data plan is for the IMs. T-mobile wont work with me to upgrade my phone with one where I can fully use my data plan. I got 6 months to go to qualify for a full upgrade, and If I buy a new phone from them (Curve, G1, Behold, Wing), will cost me in the $400 range. For that, I rather pay the $200 early termination fee, switch to another carrier and get the BB Storm for $200.
My contract did not state that these phones did not have any support for these programs. More Ironic it is, that when you upgrade (or downgrade) to their 2 year old device software, it comes with the AOL Aim. It makes no sense to loose a customer rather to help them out to keep them. I'm not even including the bad reception I have with them and all the dropdown calls
* > T-mobile