Ebay selling my missing amplifier

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.

Who have you contacted at eBay? You should contact the fraud prevention office there. Also, is your article listed in the North American eBay or in one of their other national auction sites. The appropriate fraud prevention office might be through that subsidiary's sitemap.

Do you have documentation? (Warranty registration, purchase receipt, photos of the gear before you sent it off, mail/parcel service receipts and insurance papers, loss claims, correspondence with the repair facility, documentation of their receipt of the amplifier, invoices/estimates for repair acknowledging their possession of the device, documentation of payment for service, if any,) If eBay does not respond, call them on the phone. File a loss claim with the shipper if the item was sent and not delivered. Contact the U.S. Postal Inspection Service if the USPS handled the shipment. If you can afford DarTZeel gear, you probably have an attorney who can help you. I am assuming you have recorded the eBay listing and gathered the contact information of the seller. You may need to contact law enforcement in that city to notify the police of someone selling stolen goods. Did you report the item as stolen? (By now you should have.)

Part of this makes me wonder if you are trolling. Someone who would source and buy equipment like this ought to be organized enough to not need advice of this kind.