Ebay Problems

ok here i go... any advice would be appreciated

i recently purchased a technics sl1200 turntable off of ebay. paid 325 plus 30 dollars to ship it through paypal. seller ships and ups loses package. seller tells me that ups will only pay 100 dollars and the cost of shipping back (total fo 115) and seller only is giving me the 115 back.

question: isnt it the sellers fault that he did not insure the package to the amount i paid? so shouldnt the seller refund the full amount?

also if seller wont refund the full amount is their anyway to get a refund through ebay or paypal?