sim card bad

we use new Q24 series with OPENAT applicationg in GPS terminal.
and now we find some terminal’s sim card was broken during working ,so who can tell us the reason .
thanks !
Henny Ye
Jiansu tianze INformation co,ltd. nanjing China.

Only a clairvoyant - you haven’t given any details that would enable anyone to give a reasoned suggestion!!

what I want to know is that if there is some SIM CARD bad case happened earily?