Case was dismissed but got a ticket in the mail saying I failed appear to court?

ZT ticket does not require a court appearance. It is sent into the SOS and you receive a notice your license has been suspended. As far as the speeding ticket, it's hard to day. Just show up and find out

If the failure to appear letter is based on a paperwork or data entry error, you should appear at the scheduled court date to clear it up. Judges are generally understanding of situations where you missed court through no real fault of your own. I would recommend bringing the ticket you received with the incorrect court location as well as any other proof. Additionally, if proceedings were held on your ticket by the judge and state's attorney, anything that happened or was decided should have been written on the ticket or the court file by the judge or clerk. It is unlikely that you are being charged with an additional offense or that the State is attempting to bring your case back up, however it is possible. I would recommend calling the clerk of courts for the county where the ticket was issued to find out what their computer says about your case. They may be able to provide you with some much needed insight. If you are still unsure, consult an attorney or the public defender when you go to court if you are eligible.

Do appear for the next court hearing, even if that was a mixup, otherwise you are running the risk of a bench warrant for failure to appear. Treat these things seriously, or better yet, discuss the particulars with a criminal defense attorney in person.