The buyer is responsible for buying insurance IIRC. If this was shipped via UPS or FedEx and the package was worth less than $50 the insurance was prolly already included. If shipped via USPS you could be out the money. Ask the seller if they have shipped it, how and when they shipped it, and if possible show you a copy of the invoice for shipping it. There is a service on EBay for settling disputes - it costs $20 to $25 for one version and another version is free. Look on the help page. But first contact the seller.
Use the free remediation service, Square Trade. The seller could be out of town, it's a holiday. Don't panic.
Mrs JB and I have bought and sold hundreds of things on there. Best sell - a pair of 50's-era paperback romance novels Mrs JB and I got at a garage sale for 10 cents sold on Ebay for $37. Best buy - probably a toss up between a pair of really nice congas and stands I got for $125 or a pair of condenser mics I got for $120 (normally $250). One other thing was not a deal I did directly on Ebay but was through a seller that I met there. I bought a Paul Reed Smith CE 24 with case for $700. I also replaced my bass preamp that way for $100 even though my original preamp cost $600. Mrs JB used to buy vintage jewelry on there and sell it at jewelry shows for sometimes 10, 15 or 20 times what we paid for it. Of course, we also got a lot of crap as well.
I got a 10" definitive powered sub and 3 brand new RCA satalite speakers for 250 which cost around $500
2.2 Ghz motherboard w/Pentium 4 processer tower, with a sound card, network card, and 6 USB ports, 1 Gig RAM, for $200.