> You can't sell what you don't own, so legally you didn't buy anything.

An exchange of money for an item/product is a purchase.

It might be confiscated by the Police and/or given to the rightful owner.

If you bought a thing and have the bank-/card-statement to prove the amount, you will probably get the money back, but if it was with cash, you technically don't have proof of the amount given when purchasing.