How to beat a criminal charge?

i was pulled over in michigan cause my back window was dirty i had no liscence on parole and had less than 25 grams of marijuana on me he took me to the police station tried to figerprint me but the machine didnt work i was never put in hand cuffs he gave me the keys back to the car knowing i didnt have a liscence and let me go i never recieved a ticket a few months later i get a letter in the mail saying i have court for pos of mari and driving without liscence i seen the magestrate and stood mute i have pretrial 7 20