Hello,
I hope I'm writing this question in the proper forum. I have terminated my working relationship with a computer person who created my website. I recently found out that he has created an independent email access to my email account (which receives both my business and personal emails) without my permission. He promised that he won't do this again, but I'm not sure. I'd be grateful for any help regarding how this is done, and what I should be looking for.
Thanks!

Thank you for your response.

My business email and website are served by Aplus.net. As per your instruction, I went in and changed the password at Aplus.net. I also changed my business email password (done two weeks ago before I even realized that there was unpermitted access).

I had asked my computer person to direct all business emails to my personal Yahoo email account (two years ago) so I can access both when I am away from my office. I have now changed the Yahoo password as well.

My question now is this: It doesn't appear that the computer person had created the unauthorized email account out of the hosting site, Aplus.net. Is there another way he could have done this? What appears to have happened is that he created an email account that enabled him to access all of my emails (both business and personal), out of a now defunct website, which he had created a couple of years ago.

He claims that he created the unauthorized access only a couple of weeks ago and has since deleted the account.

I'm really mystified as to how it is done, how to block it, and how to make sure that this doesn't happen again, and how to even be sure that the unauthorized account is actually closed.

Apologies for nontechnical and nonprecise descriptions of my questions. I'd be glad to re-describe according to your instructions.

I'd be grateful to any help you can give, or any referrals to an appropriate technical service source (e.g., is this an IT problem, website problem, or what?)

With gratitude,

Unless he has a filter setup which forwards all emails to your address to his too.

I have just found out that he accessed the unauthorized emails through
http://webmail.[mywebaddress]
How do I stop someone from doing this again?