Due to not having any real information, who knows?
1) Download the speedtest app, and select a server close to you from the options screen. Run 2 speed tests. Sometimes the first one can be a crap result (due to HSPA not actually kicking in yet)
2) tell us where you're at
The locations where T-Mobile's HSPA+ network are sucky are relatively few. Typically, if you've got HSPA coverage, it's good.
^ TMO HSPA+ ^---------------|------St Louis-------|----------------^ ATT HSPA+ ^
Anyway, hope you figure stuff out.
I wanted to get some ideas from the forum to at least know what to do next. Before I posted, I had already lodged complaint at TMobile and also did speedtests and didn't know what to check next - so I don't agree with your "sky is falling" remark. Also, apart from the rants on my rants (which I accept is largely due to the harsh title/contents), I did eventually get relevant replies from the forum - so I believe posting it was not a bad idea at all.
"In addition did you even consider you brought an unofficially not supported device to TMO?" - Well, for what i "read" the phone was supposed to work normally across all networks after unlocking but I guess I was wrong .
Where are you located? T-Mobile's 3G/4G isn't everywhere. Check your zip here to make sure your in a 3G/4G area.
T-Mobile 4G is located on a certain band that most AT&T phones do not have. If you have the AT&T version of the SGIII then you won't be able to access T-mobile 4G. The long and short of it is if that's the case, I'd dump the T-mobile prepaid and move over to something like Straight Talk prepaid on the AT&T network.
I had already done speed tests using same app. As others point out, at this point, it seems to be more of an issue due to the phone with factory ATT settings.
Thanks for your reply.
Like everyone had safely assumed from reading the op's initial comments: It's a user issue. Nothing wrong with T-Mobile's "4G LTE" network... He then tries to mask his technical ignorance by saying something about how T-Mobile said it was something wrong with the T-Mobile tower near op's location and that T-mobile engineers were looking into fixing it... What happened? Didn't T-Mobile fix the problem that was causing your phone to not work properly, cause again you seem to enjoy pointing fingers at parties that have nothing to do with your lack of knowledge on how to use a phone. May I suggest you switch to a feature phone? Those work with little configuration as long as the phone is unlocked and it has the proper bands.
Your attitude just seems wrong. Hopefully someone will overlook your lack of tact and throw you a bone. Good luck trying to figure out how to use your phone. About the only advice I can give is have you checked to make sure the battery is in the phone and that it's charged? Phones won't work without a battery and it has nothing to do with what network you're on.
Good luck buddy. I hope someone figures stuff out for you...
If only I could edit my original post, it would save you/me a lot of time.
Anyways, thanks to everyone for the help and I apologize for being a jerk and posting without discretion.