unlocked samsung galaxy s2 got stuck on T-mobile EDGE data network

[samsun]

i have bought this unlocked phone for about 550$, but internet is stuck on edge(not even 2g) which is incredibly slow.Please help me solve this

I have searched internet but just a few ppl has the same problem with unlocked samsung galaxy S2 and tmobile.That made me think that there might be a solution like changing the Tmobile sim card(i dont know if there is only one type of sim card), entering an unlock code provided by tmobile, or going to a samsung maintenance service and let them fix it or anyother? I have updated to the new firmware but did no effect.I cant understand how such a big company like samsungs' cutting edge new phone comes out of the factory with unsupporting the USAs one(Tmobile) of the 2(Tmobile,ATT) GSM networks data frequency..There must be a solution.I had called samsung customer service but the guy on the phone did not even know the problem.

I have found these two relevant pages but that should not necesarrily mean that there is no way because its what the poster thinks..Maybe someone can help?
http://support.t-mobile.com/message/40898#40898
http://support.t-mobile.com/message/51178#51178

[Rallyr]

I'm curious why you didn't buy T-mobile's version of the phone. I have it, with the larger 4.5" screen and 4G (I know, it's not real 4G) I've been very happy with it. I get 15-20 mbps download speeds, which are fantastic. The T-mobile version has 4 buttons on the bottom instead of the trackball, but I find it quite acceptable.

[combaticus]

I too have the same problem, but I knew of this issue beforehand. The Galaxy S II is only a quadband phone and lacks access to the frequency that T-Mobile uses for 3G/4G (Need a pentaband phone).

However, if you wait, T-Mobile is supposed to be rolling out its 1900MHz frequency network which will allow support for 3G on the Galaxy S II GT-I9100--it's already active in some locations: http://bit.ly/v24DkQ