3-4 days ago a guy from Mozilla, started to do what I asked which is getting all my 4 emails in one email, he was telling me what to do, I did. & then he disappeared

This appears to be your only post on this forum.

https://support.mozilla.org/en-US/user/alca41/

My Mozilla Thunderbird is not running well, The guy started, he was telling me what to do, I was doing it & confirm with him........suddenly he was gone

After you post here you will start receiving notifications that your conversation has been responded to, and will include a link to that conversion. You should continue the conversation there rather than starting it all over again.

Also, where ever you have been posting, you should include your version number from Help > Troubleshooting information.