eBay has a security department that can be reached by the sitemap. In the past, at least, they have had attorneys, former prosecutors with experience, on staff. You would need at least the listing number of the article you believe to have been your stolen property and probably any identifying information to verify your claim: insurance claim information, police report and any documents pertaining to the item in question (warranty papers, original boxes with serial numbers, etc.) If you were paid for your losses, your insurance carrier may have an interest, if you suffered partial loss (insurance deductible, e.g.) you obviously have an interest as well. If you know where the article is being sold from and are able to contact local authorities there, that may be another option.