Sucks but that's the way the cookie crumbles. At least its not that valuable of a book. FYI, CGC literally puts that first thing when you submit:
SUBMITTING FOR A SIGNING EVENT?
THERE IS AN INHERENT RISK WHEN A COLLECTIBLE IS SUBJECTED TO ADDITIONAL HANDLING FROM A SIGNING EVENT, WHICH MIGHT RESULT IN A LOWER GRADE THAN BEFORE.
I accept the above-described risks associated with my submission and agree to release, waive, and discharge Certified Guaranty Company, LLC (“CGC”) and its employees, agents, and representatives from all liability for associated damage, whether caused by negligence or not.