Ebay/paypal guarentee?

Hi, we purchased a tablet last december, its been playing up( shutting itself off) recently, so I've contacted seller 2 weeks ago with no reply.

I've looked into trying to raise a case but I don't think I can, am I right, it looks too late, even though its still within 12 months since the purchase.

I purchased from ebay & payed using paypal.

Any ideas or links would be gratefully appreciated.

Thanks