I took a look at the auction...the guy only has 17 positive feedbacks, and they are mixed sales & purchases. Don't install the springs at all, just keep everything together.
Sounds like he tried to pass of some springs as Eibachs and is using the misspelling "eiboch" to protect himself, at least in his own mind. Either that or he really thought those springs were Eibachs himself. Here's what I would do:
1) Contact him through eBay and cc him through personal email. Give him 2 days to respond. Also, pull his contact information through eBay. There should be a phone number listed - call it.
2) If not resolved in 1 week, issue a Negative feedback on eBay. I'm not sure how you paid...if through PayPal, try filing a dispute with them. If you paid with a credit card or VISA Check Card through PayPal, call the issuing financial institution and file a fraud chargeback. They will conduct their own investigation and more than likely refund all your money.
I really dislike PayPal, but if you did use them and paid through a checking account (bad idea), then the only thing you can really do is to file a dispute with eBay and PayPal and hope they find in your favor. Hopefully you paid with a credit card. I make it a point to pay for eBay purchases with a credit card every time, no matter what.