Replying to EBay Trouble! Please Help!

What's up guys, I recently sold my first item on eBay and after it sold it appeared on my selling reminders that I was awaiting payment for 1 item (the item I had sold) so I didn't think much and figured I would be payed in the next couple of days. So the next couple of days came around and still it said awaiting payment, so I messaged the buyer, saying I was wondering when he was going to make his payment, as I could see that no payment had come through PayPal and nothing on eBay stated that I had received any payment from what I had seen. The buyer replied back saying "I submitted my payment via paypal the day I won the bid." After reading this, I went on to discover I had received my payment and I went on to realize that on my "Activity" page it said I had received my payment. Lo and behold, I have absolutely no idea where that payment is, and it says on the selling page it says on the top "Payment was initiated on July 26 , 2011 and is being processed through PayPal." Then it posts a hyperlink saying "View Paypal Transaction", and when I click it, it goes to the Paypal log in page and says "The transaction ID in your link is invalid.". I have no idea what's going on.

So Newschoolers, do you know what the problem is, and how I can receive my payment?

10/10 K for any help, thanks!