I agree, definately need to escalate a claim as you will end up being out of pocket if you don't. You haven't done anything wrong and have been extremely patient, and it seems strange that others are receiving purchases during the time you haven't. Maybe send another email today saying that this is what you are going to do and see if they respond. Ebay will give you contact information, so maybe request that as well and give them a ring, as then they have to give you an excuse over the phone, which is a little harder than via email, etc.

Goodluck.