Hi there, I am Cris and will be glad to assist you with your question.
Was the email also deleted from Deleted Items folder?
The only option you have is to fill out this form and there could be a possibility it could be restored. This the only viable option once the email has been deleted from Deleted Folder.
I know this might not have been the exact answer you were looking for. But unfortunately this the correct answer I can provide you. Let me know if you have any further questions. Please take the time to rate my service and submit.