If you install Blesta on a subdomain or if you use the Multi-company addons you may come across the emails being incorrect for example:
You can use the following command on PHPMyAdmin in the database for Blesta.
UPDATE `emails` SET `from` = 'billing@correctdomain.com' WHERE `from` = 'billing@sub.wrongdomain.com';
If you are updating the emails on an addon company ensure you change company_id's to the correct id, the second company would be id='2'.