Rule 1 do not send goods until payment received unless you trust the buyer's reptuation on eBay with respect to the value of the goods.
Rule 2 in the event of delays keep the buyer informed.
You have not stated what the nominal win value of the item is as this makes a big difference to how much you pursue this.
Also what is the buyers country ?
From what you have said so far I would not send the item until payment is confirmed by PayPal.
PayPal and eBay are not quick respondants to e-mails, meantime I would send the 'buyer' an update at regular intervals via contact buyer only (so communications are accessible by eBay/PayPal) even just to say you are still waiting for a reply from PayPal.
Continuous updates, say weekly keep the transaction alive and avoids buyer panic when they believe they have paid and suddenly think you are trying to defraud them. the buyer could be on holiday at this time of the year and paid as they went away.
At the moment it sounds like an eBay/PayPal hiccup rather than a scam, do you know if the buyer would have received an invoice/win mail from eBay as well as Auctiva's invoice, I prefer to just use eBay's to avoid potential confusion.
So keep the buyer informed, get on with other selling and wait for a bit longer for PayPal to respond, I'd give them at least 2 weeks. Trouble is their anti-fraud etc departments are very slow and secretive.
