What can i do against it?

This question was previously answered

What can i do against them?

I'm sorry what does this have to do with immigration. You should hire an attorney and sue them

Can I petition for my parents to obtain a permanent resident card?

Yes you can petition for your parents your going to need a 601 waiver. You should consult a immigration attorney to help you with this. It's very...

My i601a application was rejected because it was not fully completed.

It seems Like you filed out the firm on your own. Maybe you should consult with an immigration attorney

If you have done all this. Next is go to your local senate office or congress office

Do I need to file for I-90 (replacement for a stolen greencard) if I've already applied for citizenship?

If you have s police report it should be sufficient. But at the interview they should let you no

This part of immigration is very complex. You should consult with a immigration attorney in your area

Legal custody

You should go and get s court order from family court. You should speak to a family lawyer to help you

H1B transfer petition pending, employment project finishing up. Can I file a new H1b with new employer?

You should consult with the company's lawyer about this. He or she can give you the best answer

Can I file N-400 while I-751 under review?

No you can not file. What if your I751 is denied. On what basis will you get you u s citizenship. Please consult with an immigration attorney...