Help Galaxy s3 T-mobile no 3G network

[Omtiesto]

hi everyone ,

1- im not in USA , but my phone model name is SGH-T999 , (when i bought my phone i didn't know that it is a T-mobile version !)
2- my issue is that my phone not connecting to 3G , even that there is an option for 3G in the settings but when i choose it the network become unavailable .
3- i tried wipe data and wipe cache , still cannot connect to 3G , only EDGE ! ( E sign )
4- I tried to install like 4 official ROM using Odin , but any of them didn't work , always received a FAILED message on Odin and "unsupported dev_type" on my phone
5- then my phone didn't turn on , ( i didnt know what to do cz i cant fix it using Odin !
6- Suddenly I noticed that my model Name is NOT GT-I9300 , but It is SGH-T999 ( i figured that in the CWM recovery menu )
7- Here i noticed that I DON"T have the "world model" of Galaxy S3 ,but it is the T-mobile version , so here i immediately installed the T-mobile stock ROM , and it worked using Odin and my phone got back to life

8- Now i just want ur help plz to make my phone connect to 3G Network
can I install the "world model" ROM for ex the UK ROM or middle east ROM ?
if yes, will it fix my problem ? if not how to fix my problem

thank a lot

 

[GTWalling]

The T999 does not have the frequencies in the Radio to use 3G overseas, 2G or Edge is the best it is going to do. If you just bought it try returning it and get the correct International version of the S3.

 

[BynoUK]

Yep, as stated there's no magical rom that will get it to work as you want it to. if you want 3G data (or H/H+) then you need to replace it with an I9300.