I too had the same thing happened to me, but on 64gb 1000x a few weeks back. I was shooting an event when it occurred. Luckily for me it happened early into the shooting so only a small portion of the shots were wasted. I returned and got another.... so far so good (cross fingers).
Like everyone has mentioned, return and either risk on another or get a Lexar. Call me an idiot, but I'm taking another risk with Komputerbay. I did 2 gigs so far (one shooting with raw and another h.264 regular format). It's been holding up good thus far.
Good luck to you