Card Reader Probem

Have been using my Comdata card for a month and a half, and all of a sudden, the card readers at the major truck stops won't read the darned thing. Do I have a damaged card, or am I being hood-winked by my Dispatcher? The card reads O.K. when the person at the fuel desk swipes it? Any guesses?

 

This is a mag strip. I tried putting a strip of tape over it, but that didn't work either. It'll be a week and a half before I get back to to the yard.
I'll go request a new one. Hope that works.

I was at a fuel stop the other day somewhere in PA, and it w as REALLY
pouring. Needles to say, I got my arse drowned running back and forth to the fuel desk.

Thanks so far for the answers. I've never had to use a Comdata before two months ago, so didn't know how they worked. Thanks.