Originally Posted by JSanders
That's not uncommon to force your device to "see" the new towers. You can always just try Manage Connections > and turn off and on your Mobile Network off and back on.
Yes, I did
But the problem keep the same.
By the way, I am from Vietnam and I posted this problem to a Vietnam forum. There are several users came and posted the same problems that I raised here.
All of them confirmed that the problem was from OS 5 because some of them are used to own a 8900 then they upgraded to 9000 or 9700.
Is this possible to find a better way?