Money orders are the safest and more secure way to do a transaction. Paypal sucks. A us postal money order is a federal issued check, which means if they screw you, its a federal offense and is something they wont take lightly. Also when sending a money order, you use the post office which is another federal program so on top of it being a federal money order, its sent threw federal mail, which they will get nailed for.
Paypal sucks because a person can send a person a sum of money, and the person can take it out instantly. Then when they dont get there item, paypal will go after them and if there account is empty, your screwed..
You want to protect yourself 110%, send a money order (KEEP THE RECEIPT!)and get a signature confirmation. There is NO more secure way to send a payment. They try to screw you over, there gonna get some jail time.
Like I said above call the number and see if it was cashed. If it was, then call his local PD. If it wasnt, talk to a rep and tell them you want it canceled and they will get a check out to you for the amount.