There are three ways of message deletion:
1) Swipe to the left:
2) To delete an e-mail:
3) To delete several e-mails simultaneously, then:
If you have deleted an e-mail by mistake, it can be restored. How to restore deleted e-mail.
Attention! Please note that e-mails, which were deleted from Trash folder, cannot be restored.
If you were unable to find answer for your question, please write to firstname.lastname@example.org