Unhappy help! my SM_N900T has lost WCDMA 2100 :(

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):
Attached Images
File Type: jpg wcdma.jpg - [Click for QR Code] (52.2 KB, 12 views)
File Type: jpg QQ??20140815110726.jpg - [Click for QR Code] (92.9 KB, 12 views)