with a usps claim...
shipper needs to go to his usps branch and file out a claims form. itll need to have your info, his info, documentation about the value of the item, and if possible a paypal receipt of what you paid for it. they will take that paperwork, stamp it, and send it to the claims people.
you'll need to go to your local usps branch with the sub and its original packaging and fill out a damage repot. youll also want to include the insurance mailing number, which will be the number on the blue sticker on the package. the green ish sticker is ussually the delivery confiormation number, and the blue ish one is the insurance number. it should be something like letter letter ### ### ### US, assuming its not an international shipment. your branch will take the damaged woofer and package and give you a reciept. they'll combine his claim info with your damage report and within about a month they'll either write off a check, or tell you guys that its teh shippers fault for being a stupid **** for not packaging this heavy fragile item better. if the package looks like it was packaged well and is still damaged, you'll porbably get a check from usps.
when the shipper fills out the claim fornm they have an option to choose who recieves payment, you or him....hopefully if he gets the $$ he send it to you. if it looks like the undamaged parts or unusable the go for the full refund. last time i had to do a usps claim it took about 3 weeks to get a check.
hope this helps.