Just show up on the court date, hopefully the officer who gave you the ticket won't be present, the judge will dismiss the ticket. Even if he does, say you made a mistake and if it is your first offence, they might cancel it as well. Or, do the defensive driving course online which will cancel the ticket, if your state has that provision.

If you indeed used your cellphone while driving, then your are guilty. Just admit it and show willingness to correct the mistake, and the judge will be happy. He will give you a break. You say, hey i'm not guilty, you are inviting more trouble.