[Iyanga]

Easiest would be to do most of the work in the MAIL_REMOVED event.

When you want to start the mail delete action:
You store the mail info you want to delete in an array and a counter as index where you are.
Then you delete the first mail only.

The MAIL_REMOVED event increases the counter and just deletes the one mail the counter points at.
It stops deleting the mail, when the counter is higher than the count of items in the array.


This way your delete action automatically gets triggered once the previous one is finished, as it is done by the MAIL_REMOVED event.