I am a SM-N900T user in china; I had used China union(like T-mobile in USA) for three months well and i can't use 3G a week ago. IF I chose WCDMA ONLY ,my phone turn out to be no signal . so i typed *#2263# and found the "service mode" - WCDMA BAND preference did not has WCDMA 2100, i am comfused. As printed on T-Mobile homepage, the SM-N900T has band 2100, so could someone help me ?
China union : WCDMA（FDD）：