I Have A Problem In A Ebay Purchase...

I made this year some stamp purchases in ebay, including in auctions. All my purcheses are around US$ 10 or 15 dollars and I never get any problems. In my last purchase I get an unsolved problem because the 'system' didnt allow me to pay using paypal or credit card. I wrote 3 messages to the vendor and he didnt answered. The vendor is from my country (Brazil) and have a high level of feedback. I couldnt find some place in ebay to communicate this issue. I think I felt in a kind of 'black hole', as now I am in debt as I 'didnt pay' for the item. Anyone did experienced such situation in ebay?

I once had an odd experience when I won an item, paid by Paypal (money in both my Paypal account and bank account) and the payment wasn't made to the seller. I never understood what had happened, but seem to recall that it might have been some one-in-evry-million-transactions Paypal measure. In my case, the seller at least received some information from ebay/Paypal and simply cancelled the sale.

Several times Rigel, but not with stamps,
I have bought several items "Buy Now" and going to Checkout, it informs me that the vendor "does not post to PO Boxes"
So I leave, then I get messages from ebay to pay up.

Annoying, but fixable by emailing ebay.

I sent a message to ebay and still waiting an answer. My only guess about this issue is the fact that the vendor is from Brazil enad I live here, so maybe he dont accept the buy from here... I cant find another explanation. I tryed many times to pay, but ever received the same system answer. The paypal and credit card arent accept . Thanks for the anwer GeoffHa and rod222!

Rigel,
just relax, you have done the best you can.
Ignore the experience.
In perhaps 10 days or so, ebay will send a reminder of your failure to pay,
That offers you a time to reply, as to what happened.
You have nothing to fear.

Situation fixed, at last.
Thanks to all!