Public Defenders are over worked and under paid. Because of this some Public Defenders are slack on their job to the point of even refusing to contact their clients prior to trial.
In any case if you feel that your Public Defender is not working in your best interest because (s)he fails to visit or meet with you, or does not return your calls, you should request the court to appoint you another counsel.
It is an attorney’s duty, whether a public defender or privately employed by you, to be diligent in keeping contact with you. A common complaint is that they fail to communicate with the defendant prior to trial. Communication with your attorney is a must and you and your defense counsel should agree upon defense strategy. As with all cases the pretrial work begins with a meeting with you. Communication must remain open throughout the investigation phase as well as the trial phase of your case.
In most jurisdictions a "Marsden Hearing” is allowed. This hearing is to allow the court to hear the defendant's problems with their court appointed counsel giving the court cause to appoint new counsel. However you must show the court serious problems, such as lack of contact and/or communication. To seek a Marsden Hearing, write a letter to the judge, requesting to a meeting with him regarding your appointed counsel. Send a copy to both your counsel and the prosecutor sending all copies and the original (to the judge) via certified mail, remember to keep a copy for yourself. This letter should state all problems you are having with your attorney. Keep the letter concise, compact and truthful do not jeopardize your honor before the judge by stretching the truth.