Help with Automated Emails

Hi, I am new to S2Member and have tried to set EOT time to reset all members to non members and then send and automated email 1 hour after expiration. However it didnt send and I dont know why. Is it because members roles changed instead of being expired?
I have now changed the email settings to 1 day after changing users role in the hope I can catch this and still send.
My alternative is to try and make all those users a different membership level again and undo and start again - can anyone tell me if this is possible and how I would go about it please ? Or if it is possible to find a log and choose those members that were just downgraded somewhere and send them the email manually ?
Thanks for any help