On the morning of a debit (Tuesdays and Fridays), at approximately 9:00am AEST, we pull together the list of members across the clubs who are going to have their bank accounts debited. They get sent a notification at that time about the pending withdrawal.
The notification states that they have a three hour window to let us know if the withdrawal should not happen for any reason. There is no point attempting the debit and suffering a rejection fee if there is no chance that it will succeed.
If a member contacts us to pull out of the debit run, we cancel the withdrawal. The member receives a notification to that effect, which we also CC the club Treasurer (or Administrator) on.
The downside is that it pushes their entire schedule out by one week, but this would happen anyway in the event of a rejection, so we do what we can to be fair about things.