Legal Question in Business Law in California

I will be happy to review the subpoena you without charge. The subpoena may not require a court appearance by you.

Lawyers sometimes make mistakes. It's possible that the subpoena was filled out incorrectly. You seem to think the lawyer did this on purpose, but that is not likely.

People who receive subpoenas sometimes make mistakes, too. I can't say whether you did or not, since I have not seen the document and I don't have enough information about your efforts to comply.

Another possibility is that the court changed the date of a hearing or trial after the subpoena was issued. Courts often change their calendars around, and while the parties are (at least usually) notified by the court, witnesses generally are not. My suggestion would be that you contact the attorney that issued the subpoena. Disobeying a subpoena, no matter what the court clerk tells you about the court's calendar, is not the best course.