After 48 hours the message can't be deleted. Even if you postpone it it is not being deleted from chat.
What to do:
a) Catch and put a message: can't be deleted, pls, remove manually.
b) Edit(is it editable in 48h+?) to something, at least remove buttons so that it's not postponed multiple times.
c) If it's already 47+- hours passed and noone taken any button action, then just resend it at the same interval.