Ebay selling my missing amplifier

@wesheadley "As far as contacting the local police goes, good luck with that. I would be amazed if they got involved at all. BTW, it sounds like an interstate situation, so that would involve the FBI -- speaking from my own experience, there is absolutely no chance those guys will lift a finger to get involved in a situation this. They'll tell you they're understaffed and can't devote the resources."

+1 Some of the other posters are in a fantasy land thinking that the police are going to make this a priority of any kind. And, yes the Feds wouldn't even waste time taking a report on this, much bigger fish to fry.

If the OP received any monetary settlement with the shipper for the lost shipment then he no longer has any ownership claim whatsoever.

Contact the shipper, USPS, DHL, FEDEX, UPS and open up an investigation. I know USPS has an investigation team that deep dives this stuff in coordination with the FBI due to the criminal elements being involved. 

Above posts are correct.  If the amp was insured and you were paid the insured value, you have been made whole and have no title or rights to the amp.  The insurer is the amp’s owner and may or may not choose to take action.  The legal exposure of Cargo Largo depends on whether they are a bona fide purchaser, meaning they gave value for the amp without notice it might be being sold by a thief.

You could buy the amp with the insurance proceeds, of course, and maybe even come out ahead, if you can negotiate a good deal.

in 1973, my 1969 Les Paul Custom was stolen in a burglary.  I’m still looking for it!

@audioquest4life "I know USPS has an investigation team that deep dives this stuff in coordination with the FBI due to the criminal elements being involved."

That may well be but the FBI isn't going to focus on some potential one off maybe theft of an amplifier.