Hi bluebidzer - Before you buy another thing on Ebay, familiarize yourself with the rules.
It is my understanding that you can start a Dispute in EBAY very soon after paying if the seller is not replying to you. Make sure to only email from inside Ebay - that way the Staff at Ebay can see the correspondence you have with the seller. If you are concerned File a Dispute. If THIS doesn't get a response then Escalate to a Claim through Paypal, but you have to do these steps within 45 days.
Being Fair to Sellers- sometimes sellers are away - or ill - or are just very busy or have any number of issues that delay responding, so the Dispute system is the fairest way I can think of.
Often the Dispute does not escalate to a Claim, it is resolved, but DO NOT close the case until you have your item or your money.
I hope that is useful.