They aren't asking where you were, what matters at this stage is where the car was.
By 'ticket' I assume you mean a NIP and s172 request. You must reply to that - an email isn't enough.
If you're absolutely certain it's not your car, and not a number mis-read, you need to report the cloning to the police and DVLA. When you reply to the NIP give them details, including the crime number if you get one.