Well, first of all they had to have booked you on charges in order to arrest you. So are you saying that they dropped the charges after holding you for a month? There is a difference. By law you can recieve all the paperwork of why you were in jail in the first place its called PUBLIC RECORDS~! so if I was you I would find out WHY they arrested you in the first place and see whats going on. Then if you cannot get any answers then I would go to a Legal Aid Center or your Local Law Library at your County Superior Court, usually there are lawyers who volunteer pro bono work that can give you more precise advice according to your individual circumstance.
btw- lots of people get arrested on bogus charges and once you are set free you usually can't do much about it....but best wishes for you to take care of this-