If you got the message I sent yesterday in your email, it is because you have the option turned on indicating you wish to be advised via email of new private messages. I sent you a forum private message, not an email.
You can modify the settings for pm notifications here:
https://www.susans.org/forums/index.php?action=profile;area=pmprefsYou can change the settings for topic notifications here:
https://www.susans.org/forums/index.php?action=profile;area=notificationAgain the control of the option to have (or not) notifications of new private messages and topic replies sent to you via email is entirely under your control. It is very rare I contact anyone via email without you, emailing me first.
You are free to disable email notifications, or request deletion; otherwise you will receive private messages like all of the other users do from time to time. This is not optional, and you cannot opt out of them.