I've been paid by winning bidder via PayPal...safe to ship item now?

[pinkoos]

Since I'm not very experienced with this, I thought I'd check with you guys.

The winning bidder has paid the full amount into my PayPal account. My PayPal account shows the payment as "instant."

Now, is it safe to go ahead and ship the item? Is there any way the buyer can "retract" the payment or something fishy like that after I ship?

Thanks for any enlightenment!