回复：Thank you for your info. Signature Question.

I am wondering about that too, but probably signature is too technical to decide, so that's why once you get your credit card lost,you need call the credit compay ASAP.
but if you never lost yours, then that means the one they use is the fraud copy, probably you still have chance to get back.
that's only my guess, you need continue to work and argue with your credit card company.