Click on the ticket. Then click on the blue contact name. In the example below, click on itycm beside the green icon so that it brings up contact information and not the ticket information. Don’t click Edit on this line:

CONTACT DETAILS | Edit

as it only brings up the ticket information (and the contact won’t be deleted).

You will see this:

Select Delete and you will see this:

Select Confirm – this contact will be deleted and all future emails from this email will automatically be sent to spam.

Then click on the ticket and delete it.