As a publicly traded company, you'd think eBay would have some sort of Ombudsman or Compliance Officer to escalate alleged improper/unethical employee behavior. Perhaps with a little digging, the identity of that type of person could be uncovered. (The regular complaint process is not appropriate because the issue is with an employee -- not with a transaction.)
This page at eBay, Inc. details the Board of Directors and also features the eBay Employee Code of Conduct and Ethics:
http://investor.ebayinc.com/governance.cfm
If it was me, I'd try to find an Ombudsman. If that did not work, then write to every member of the Board of Directors until I got a satisfactory response.