Sending as F&F also reversible. And even if it cross 100 hands yet it will reverse. For example, you sent me, I sent to a, a sent to b, b sent to c, c sent to d--------. When there is something wrong payment should be reverse from me. If I have no balance then from a, if a has no balance then from b, if b has no balance then from c, if c has no balance then it will reverse from d, if d has no------------------------------------------------------------------