I need some advise on a shipping disaster.

I recently purchased a pair of speakers on Audiogon.  The price I offered was accepted and I sent the payment promptly.  The seller in return shipped the 2 speakers promptly and sent me the tracking numbers.  One of the speakers was delivered the next day and UPS has lost the other speaker.  The seller has put in a lost package investigation however UPs has not recovered the speaker.  It has been 8 days since the lost investigation has started.
I come to find out that the package was only insured for only half of what I paid for the whole package and it would cost twice that to replace the lost speaker new. So even if UPS cannot find the speaker and pay the insurance claim I cannot even replace the missing speaker for the amount of the claim.  
I'm not sure how to go about solving this issue.  I purchased and paid for a full set of speakers and only have 1.  
Any suggestion on what I should do next?  Has anyone ever experienced an issue such as this?  Does Audiogon have policies around issues such as this?

Thank you,
Vince