I had the same problem happen to me a few days ago, i spoke to paypal and they said if the process doesn't finalise you'll automatically get refunded, because i spoke to them on chat i think they made the process happen faster.

What happened to you, that it says you didn't pay for the item, it won't do through and your order won't be completed, and paypal blame it on a glitch with the seller's website, i would like to know who's fault it really is, i tried to pay for more than one auction using pay in 4, and i had the exact same problem that it took my money and didn't finish the transaction, and had to speak to someone on paypal chat messages to reverse it.

They told me to clear my cookies and cache, etc... and that didn't help, i even tried using two different browsers, be warned if want to pay with pay in 4, it might not work.

I wasted too much time, don't even try if your not prepared for the risk.

This def sounds like something to do with paypal. I agree with the other user who commented

I think you need to check your PayPal account