I would flush the letter down the toilet if that tells you what I think about it. If you get charged with a crime, contact a criminal defense lawyer and use the $350 you saved to hire him/her. www.giardinolawfirm.com
Your priority needs to be the criminal case. There are many ways to prevent a conviction and ultimately get the case off your record. If you don't already have a defense attorney, start looking for one now. That letter is requesting payment of a civil penalty. It has NO AFFECT whatsoever on the criminal case whether you pay it or don't pay it. If you don't pay the civil penalty, the company does have the right to sue you for it. However, I have never seen them pursue that right.
Macy Jaggers's answer to a legal question on Avvo does not establish an attorney-client relationship. Ms. Jaggers offers everyone a free consultation to discuss their case. Feel free to call her office at 214-365-9800 to make an appointment (phones are answered 24 hours) or visit her website at www.macyjaggers.com for more information about her services and recent victories.