Do you have a credit card attached to your Paypal account? If so, they will charge your purchase to your credit card.
You will owe the bank, for the bounce, you should call paypal, and find out if they resubmitted to the bank, luckily the seller cant grab the money and spend, it as you would be maybe liable for his bounces too had he spent money he thought he had. Yes you are in legal trouble if you dont rectify this in the time frame they set for you, the bank, and pay pal, spending money you dont have, is illegal. The person who did a great job at trying to satisfy you, will most likely never do that again if it causes him a problem, but usually pay pal makes sellers wait a few days, to ensure the money clears, unfortunatly, sellers who are trying to be good sellers......well u know the answer to that.
The buyer shouldn t have shipped until the funds cleared. That is beside the point though. It depends on how paypal handled the transaction. You either owe paypal or the seller. If they can prove it was intentional then they can press charges for fraud. If it was accidental it will be a civil matter.You either need to try to correct the situation with paypal or return the camera to the seller.