On my nonimmigrant visa i stated I was married my us spouse filed my i130 went to the interview then got a letter from uscis

If you were married before you need to submit a divorce decree as you cannot be married to two people at the same time.

I was born in US, i was days old when my parents left US

It is best to consult an immigration attorney. This is a complicated fact pattern and you need an attorney to assist you.

Yes you are allowed to take a brief trip.

Were can I send a mercy letter in regards to a person that is currently held in ICE custody for deportation.

Send it to the deportation officer where he is being held.

Can I file for EB2 petition on F1 status? Would the denial of my H1B adversely affect EB2 petition in any way?

It will depend on the employment position. Consult your potential employer's immigration attorney.

What is the processing time for people in first preference category(e.g. Unmarried, adult sons and daughters of U.S. citizens )?

This depends on the country of birth. You can consult the Dept. of State visa bulletin.

When I eligible for citizenship

Need more facts. Are you a green card holder? When did you get it? Generally you need to have a green card for 5 years to apply for citizenship.

How I get approved for my I-130 case

As a sibling you have over a 10 year wait. You can consult an attorney but they cannot speed up the process.

Will i qualify for a provisional waiver form I-601A if i have kids under age 13?

If you entered the country lawfully, then you probably do not need a I-601A waiver. It is best to consult an attorney. Are you married to a US...

How can I protect myself from false domestic violence allegations made in order to pursue VAWA green card?

You might consider hiring a criminal defense attorney and perhaps an immigration attorney.