Yeah, I entered an rma yesterday. I'm not confident SanDisk is going to accept the Amazon invoice that says it is a "used" card. Also not confident that if they do accept the rma, that when they receive the card they find it to be a legitimate SanDisk.
I was able to get it formatted by doing a full format, but it still failed during the h2test after about a gig of written data.Also had slow write speeds, only about 40mb/s.
Started the return process with Amazon as well.