the saleman in AT &T shop lie to sell staff, do n...

the saleman in AT &T shop lie to sell staff, do not belive what they say.
and their manage just let he do it.
I walk in and ask a SIM card which can used both in China and US. they show me and sell it to me. but actually it does not work at all. they keep saying it is misunderstanding, no refund no solutions.
while the T-Molie nearby is honest and direct says T-MOBILE have no service in China. I do not see any misunderstand.