Just because you'd THINK you're in a 4G area doesn't necessarily mean you really are. There's areas in Atlanta that still aren't 4G.
Make sure you use the MAGENTA DATA map (not the GREEN VOICE map) in the above link. Although the shades of magenta are a little tough.
Is it safe to assume you're using a T-Mobile Branded Samsung Galaxy SII and not a non-T-Mobile device?
Hey fugaz, these guys are right pulling the battery and doing a manual network selection as well as checking the coverage map are great steps to take. Another good step that would narrow down where the problem is would be switching sim cards with your brother, if you see 4g on the Sensation with your sim card in it then you know it's not the account and the phone that is the issue, I would recommend trying his sim in your phone as well just to be thorough, Post the results here and we can further assist you.
hi, thanks for replying to my question.
This issue has quite a few days, I've tried restarting and pulling the battery out and pretty much all those things mentioned.
I live in a great coverage area, I've checked the map. and also move around a lot, but I've never seen my phone switch to "4G"
The only thing I need to do now is try using my brother's SIM Card, I will do that when I see him so I'll update this post later.
I'd disable auto sync of your contacts if you're going to do that, otherwise (if either of you use T-Mobile contacts backup) you will find your contacts get blended.
Settings-Accounts/Sync and disable AutoSync. You can enable it later, once you remove your brothers SIM from your phone (or do this on his phone...either way...) once you're done.