How do I answer this summons,is there a form, do I write a letter, do I call them? What are the procedures to fight back?

What type of case and what State?

Depends on the case. Is it civil or criminal? The best way is to hire a lawyer.
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Los Angeles Attorneys (http://www.personalinjurydefenders.com)




This is totally insufficient legal advice and I find the posting of this site to be against board policy. If you can't offer legal info, please don't post. You are obviously affiliated with the personal injury law firm which operates this website.

Too bad the OP isn't interested in personal injury law.