Do I have to go to Court Witness

Do I have to go to Court Witness

I had a accident on Oct , 2005 last year. Another drive is fault. Police man came and gave another driver careless driving ticket. Now I got a mail for witness this case because another driver isn’t happy with ticket and choose going to court. I am busy at that day.
Do I have to go there for witness? Do I have to call and tell them can’t go. I am trying to call and difficult to get though. Thank you for suggestion. I am in Florida.