Your lack of action is definitely a contributor.

You don't seem to have even checked the tracking. Or did you send a $2000 item without tracking, or signature on delivery?

As an aside, not that it will matter as suspensions tend to be permanent, ALL buyer messages also come through your eBay messages.

YOUR lack of action, especially given the value of the item, has led to your suspension. I doubt you will find many sympathetic sellers, and no sympathetic buyers.