If you are subpoenaed as a witness, then you will not be able to get a public defender. Public defenders are given to people charged with crimes who cannot afford to retain counsel of their own.
If you appear in court, you must answer the questions you are asked (assuming that answering them does not in some way incriminate you in a crime). If you refuse to answer, the judge has the option of finding you in contempt of court. The penalties for this range from a fine to jail time.
If you are worried about appearing in court, I would consult with an AZ lawyer.
I'm not authorized to practice in Arizona, but in federal court, judges can appoint someone to answer the legitimate questions that you have. You definitely should speak to an attorney if you are concerned that a truthful answer to a question may incriminate you or even reveal that you lied to an investigator. If the judge can't appoint an attorney, check with the local bar association. Many have lawyer referral services in which attorneys will meet with prospective clients for a modest fee. Good luck.
THESE COMMENTS ARE NOT LEGAL ADVICE. They are provided for informational purposes only. Actual legal advice can only be provided after consultation by an attorney licensed in your jurisdiction. Answering this question does not create an attorney-client relationship or otherwise require further consultation.
A subpoena is a court order. If you fail to obey it, the court could issue a warrant for your arrest.
If you are called (by subpoena) to be a witness at a hearing or trial, and the questions you are asked might incriminate you in some crime, you must tell the judge that, and ask that an attorney be appointed to represent you.
If, on the other hand, the questions and answers will NOT incriminate you in a crime, you must answer the questions.
As the previous attorney instructed, if you are on the stand and refuse to answer after a judge orders you to do so, even if you have said you are afraid of incriminating yourself, you must answer the questions truthfully, or the court may hold you in contempt.
Your fear of incriminating yourself must, of course, be real. You cannot pretend or use that as an excuse if it isn't true. However, most judges in Maricopa County will, if they believe there is a real threat of incrimination, will appoint a lawyer to represent you on that issue alone.