Just paid for someones upgrade and haven't recieved the bid money, and the auction is still availble in the upgrade auction.

I had this happened once, ended up being the transaction never went through, just check out your paypal and I bet it didn't process fully. The only auction I am seeing of yours the player cannot afford the upgrade, so that one would not go through as the player cannot pay for it.

Also as Sam said in the news:

"P.S. Due to the high volume of internet sales on the Thanksgiving weekend, PayPal may be running a little behind. This means that your upgrade or Horse Bucks may take up to 30 minutes to show up on your account, but rest assured that they will!"

I am assuming that can apply to the upgrade auctions going through.  

What Con said. :P  If it hasn't gone through after an hour or so please contact Sam directly and she can help you out. ☺

Thanks guys:) Samantha has been very helpful in fixing the problem!

it has happened to me a few times, but it always goes through eventually xD