Hi my name is Esteban

How can I find a dial tone after AT&T make a mees my system

Contact AT&T tech support. They own the lines.

I would disconnect wiring into building, to determine their problem or yours, if on yourside, they will charge you.
Call your number, if it rings and rings, line is open, if it rings busy, it has a short or phone off hook.

You should have a small grey box on the outside of your house or office. Open and plug an old analog telephone into the jack inside the box. If you don't get anything disconnect the wire going inside your build and try again. If you then get dial tone the issue is in the build.

Hi, 123esteban!

What specifically, did AT&T do to your telephone system, please?

Thanks!