What can I do in this case ?

File I90 and check card issued but never received. Also call the National Visa Center to see if it was returned to them.

Best to see an immigration attorney in person for a consultation on your case.

How long they i need to way for apply again for n 400?

You can reapply anytime, but make sure you are fully ready to submit all documents to avoid a denial.

Can i apply citizenship with a unexpired lost green card?

If you have a copy of green card, use that with your filing for citizenship.

What can i do if a judge ask me for immigration status in my next court ?

It’s definitely in your best interest to talk to an immigration attorney.

What should we do if my fiancee has different name on his passport and birth certificate?

He should make the correction first.

As stated above, as long as it’s a valid marriage, you can petition for her to enter the US.

Change of my Date of marriage in uscis ?

Take it to your interview and while under oath explain the correction and submit the corrected marriage certificate.

I would hold off filing the N-400 until you speak with an immigration attorney.

When should I apply for a green card and work permit after marrying a U.S citizen while currently on a F1 visa status?

You can apply once you are married. Your work permit takes 90 days from filing.