Buyers order not showing up or going through on my end

[coin-kingdom]

So a buyer has bought an item for me in a quantity of 2. There were 3 in stock, and now when you go to the listing from the buying end it shows that there is only one item left. The buyer has shown me his order number along with a screenshot of his order with a timestamp, and it says that he has paid and looks proper. However, I have not gotten a notification that the order has even come through, and when I go to the item through the seller backend, it still shows a quantity of 3. I have not gotten money through paypal yet (my paypal email is correct for this listing, just checked). I have not shipped the item yet, but I am wondering why there is some sort of delay between the buyers order and my end.

Thanks for any help you can provide.