Good to see that as a newbie you are giving priority to forum PM rather than email or telegram chats and its the thing which can save many newbies from getting scammed. After reading your description it seems to me that whenever you get agree with him to use escrow service for your bitcoin selling you may shared the escrow name with him and he tried to make you fool by sending emails from similar looking email address.
Though your story isn’t complete and kinda hard to get exactly what you are trying to say. I think you are trying to say that the same user have used multiple account and contacted you to complete the deal. Whenever you cancelled one then he came through another one and tried to act like trusted escrow service providers. Right?
Sorry to say that you haven’t added enough evidences on your topic and i will suggest you to add your conversation screenshots to make your accusation stronger.
You can use this escrow service
Escrow Service of Bl4nkcode [Active] and his service is
Active now. Don't forget to send him PM first.