I've had similar problems at wally world. Found out the problem was with the dumps I had. All the dumps I had were same bin,all were sniffed and from the same base. After six stores all swiped with a different dumps(never swiped same card twice) the bin went dead. Went to a few more stores and all decined,,went back and dump checked the rest and they were good. Got new dumps,,same bin from different vendor and didn't have anymore problems. Seems the first base I started using was a couple weeks old and they were able to shut it down quick. Last dumps I used were two days old and swiped perfect without any problems. I think since alot of these sniffed dumps come from same pos terminals,,it makes it easier for banks to spot fraud and limit other cards from their bank used at same pos terminal. Just my own personal experience with sniffed dumps,,,