...and that I must leave positive feedback for the payment to be released. He says he won't ship until payment is confirmed.

I've had more than 170 successful eBay transactions in over 4 years and I've ever heard about something like this from any seller.

Some details:
- Seller is in the US and me in Mexico but it's always that way.
- I recently registered a new shipping address at eBay/Paypal because I learned that I had the wrong zip code before (never had a problem though since the wrong zip code is adjacent to mine). The address linked to my credit card is the same but with the incorrect zip code. Anyway, I've bought 10 or so items since then without problems.
- The transaction details page at Paypal doesn't say anything about a holdup.

So the question is: is him pulling my leg? He has good feedback (98%) but almost every negative seems to be from an international buyer.

Of course I wouldn't ever leave positive feedback without having the items in my hands, so if what he says is true I guess I'll desist.

Sorry if this isn't the appropriate forum to ask. Seemed to be the right one.