Can someone PLEASE offer advise/help?

Hi,
Let the nightmare begin.

I sold my Canon 85mm 1.2 ll on Ebay foe 1500.00. After receiving Paypal payment I asked my wife to drop off the box at Fed Ex (office is across the street from her job).

I requested her to get insurance for 1500.00 and to get the " signature required" option. She was in a rush and did not get the insurance but DID get the "signature required" which cost a couple of dollars extra.

Well I tracked the shipment and show it was delivered and left at the door of his private residence EVEN THOUGH A SIGNATURE WAS REQUIRED!

You guessed it......the package was apparently stolen because the customer never received it. I trust the customer because he was the one who requested that I get signature required to protect both of us.
Fed Ex is re-tracking it and said they will get back to me within 48 hours.
Now my questions.

I know the package did not have insurance (please no comments about my wife!....she feels terrible). However isn't Fed Ex responsible for this loss? The insurance is for lost or stolen goods (while in their possession right?). It WAS delivered but without the required signature (which IS indicated on the tracking info on their website) and on my photocopy of the Fed Ex shipping label.

I feel I entered into a contract with them.... paid the additional charge for the signature requirement and they failed to carry this out.

I would really appreciate any advise or comments so I know what to do going forward with this. Needless to say this is very very upsetting and I don't know where else to turn. Thanks!! Bruce

--
BRUCEK56