I would call as I do not believe the postmark matters; the funds have to be removed by 04/15, especially since that is how you filed your 2018 tax return. If they don't remove it by Monday, your 2018 return not only needs the earnings income, it will need the 6% excise tax on the contributions as they will not be considered ''removed'' in time to avoid the penalty. You should be able to talk to someone Monday and confirm they have the form and did or will remove it by the end of the day. They should understand because this is a common issue they deal with every year at this time.
