Contest, contest, contest! I get them all the time. When they send you a date for the court hearing it will have an option to write out your defense if you are unable to make the court date for whatever reason.
I get tickets when I'm in a place I'm allowed to park and when I've paid for parking and have it properly displayed I still get ticketed. I even asked the judge if it's common practice for the city to hire incompetent parking enforcement officers.
I've also gotten in verbal arguments with Parking enforcement. Once it got so bad I asked how they felt they didn't cut it to become a real police officer. Didn't make my situation better but I got out of that ticket when I met with the judge.