"Escrow" means the middle-man of your transaction which means he would be the one to held up with the funds until the product or item is already being sent out to the buyer
and that time the cash being held by escrow would be released to the seller itself and thats how the system works. Since you are delivering the item (seller) then there would always
be a policy on pay first before sending because on that kind of arrangement it would be too hard if the receiver wont tell that he recieved the item and tell the escrow to refund the funds.
There would be a tendency like that and it would be much hassle to make verification on carrier on where that package goes. Better to have payment first policy or COD (cash on delivery) method.