Am I getting scammed?

[asut4126]

I am quite new to selling on eBay, so excuse my ignorance as to how some things work...clarification would be most helpful

So an auction of mine just completed.  Before I sent the invoice (are buyers prompted or allowed to pay before receiving an invoice?), I received a message from the buyer stating, verbatim:

"payment sent, my credit card was charged, it will be pending balance till the item is shipped and delivered."

So I replied that I had received no notification of any payment via eBay, and asked him to pay using the invoice I sent (I have always received a notice from eBay when other people have paid).  He marked "payment sent" on the item, but it's just an hourglass symbol in my dashboard.

His reply: "as i said the funds were send but its pending till the item is delivered."

So I went and checked my PayPal.  There is no pending transaction for the amount the item sold for.  I have yet to contact PayPal directly, but I would imagine even a pending credit card charge would show up immediately, but just be marked as "pending" right?

I told him that I didn't see anything, and asked him to cancel whatever payment he thinks he sent, and remit using the invoice I sent.  Now he's not responding at all.

Is this guy trying to scam me?  What should I do?  It seems very sketchy, even how from the moment he won the auction he claimed he sent payment, before I calculated shipping or anything.  I guess I can be patient and see if anything shows up in my PayPal over the next couple of days, but I'm already still having to wait two weeks for payments to clear, and I really don't want to drag this out any further...