Why don't you try a different knife? I don't want you to get the same knife and have it happen again.
Try this instead. When you are done with using the knife wash it and dry it and you should have no problems. Drip drying the knife can stain many kinds of stainless steel so don't do that.http://www.chefknivestogo.com/satadahasa18.html
I'll take your used knife back, refund you minus the restock fee, charge you for actual shipping back to you, and ship you this knife as a replacement. I'm pretty sure you will have no problems with it since it uses a different stainless steel that I've never seen react or pit like yours did. Just don't wash it in vinegar and you should be good to go.