Millions of people have had access to their email compromised by someone gaining unauthorized access to their email account. Sometimes this goes unnoticed for a long time giving the bad actor to be the man in the middle or use your account to hide their tracks while defrauding others or start sending spam.
Usually, people only notice that their account has been compromised when their contacts complain of receiving spam. The man in the middle or illicit use of your email account is hard if not impossible to detect. We can block the unauthorized access to an email account by changing the password. Hopefully with a strong and unique password and enabling their 2 step verification/authorization.
Changing password is not enough to stop unauthorized use of your email address! A smart hacker can set some simple rules in your email account to automatically process and forward email regardless of how often passwords are updated with strong ones. These filters continue to keep doing their job of the hacker well informed about emails flowing through your email account.
Checking your filters
Log into the web version of your email account. For example iCloud.com, gmail.com, yahoo.com, etc. Open the filters page under settings. Verify that any “rules” or “filters” that might be present and delete anything suspicious to you. Just in case you are ever contacted by law in force not it wise to make a note of the settings or take a screenshot of any suspicious rule before deleting it.