Questionable License Suspension

I work full time and I began graduate school this fall, I am also a forgetful person. when my Inspection sticker ran out (I am in Mass by the way) I didn't even notice. I was so busy that I just forgot. I received a ticket for having an over due inspection sticker, which for some reason they didn't leave on my car they sent to me in the mail a Hand Written ticket (Seems questionable right?). To make a long story short, I received notice last week that if I do not take a driver retraining course I am going to loose my license! In the past 3 years, I have received 1 speeding ticket and (in the same incident) a ticket for driving in the HOV lane. I am BEYOND confused, I am not some sort of degenerate, that speeding ticket was the first I have received in my LIFE. I really just need to understand my rights, because from what I am reading it appears that I have none and that they can force me to pay $125 to take a retraining class. Any advice would be great.

Thanks!