Ok, sorry, I keep getting the scrap mixed up with your other ventures lol.
Not quite sure what that paypal request is all about, but something is not right. Did the supplier send you an invoice for the purchase through PayPal, if he didn't, ask for him to send you a PayPal money request for the correct amount, that will also provide you with a PayPal invoice.
Always much better to have a PayPal invoice in case of any dispute that might develop.
Regarding if they will take funds that are owed automatically, the answer is yes, but only if you owe it. They will not take your funds if someone else claims you owe them.
If any transaction is in dispute, they have a claims process that has to be followed, then if the two parties can't come to an agreement on their own, PayPal will make a determination.