I've received funds from someone in Mexico with a USA post office box where there is supposedly someone to sign for the package I am to send (sporting good item). They are verified, the post office box address matches their Paypal account, but since they sent funds without indicating they are paying for an item, I am wondering if they can retract those funds after I send the item.

Can they retract the funds?
Please advise.

My actual (logged in) paypal account gave me all the above info, not an email.
Thank you all.