Do NOT contact ebay through their contact links. Those CS people are outsourced help and don't have the power to do much more than tell you what you want to hear.
First and most important, respond to the chargeback with a brief and factual reply stating that the item was authenticated and found to be as described through the "authenticity guaranteed" program. Explain that ebay closed the dispute in your favor since you have a no return policy and item was found to be as described.
What you should do next is contact ebay through either one or both their Facebook or Twitter pages. Those sites are manned by real ebay employees who have the power and ability to access your account and see what's going on.
Log into Facebook to start sharing and connecting with your friends, family, and people you know.
www.facebook.com
Don't post publicly. Send a message through their PM. They'll verify your identity and help you.
I don't use Twitter but did have occasion to use the messaging through FB and got my problem resolved within hours.