Kingston cards are among the best. However, try another card. Reformat the card as well, any card can be corrupted if the camera door is opened, for example before the file has finished writing.
I've used fast, slow, and even cheap cards in my 5D MK II with no issues, so, since its a new camera, if a different card does not solve the issue, I'd say the camera has a issue and return it for another.