Set payments as "Family and friends"

Hey, I'm looking for a way to set a payment without charging any fees to any of the users involved in the transaction. I know I can set up a payment_type as `PERSONAL` and I believe this is the option I want. So I setup this option as well within the `receiver_list`key but is not working. the fees are still being charging.
Do you know something about this?. thanks in advance. 
