write a letter or respond to the summons. I am not licensed in California so I cannot officially represent you but it should be simple to respond and also to threaten them for this conduct. See, e.g.,

https://www.edalaw.com/understanding-californias-1287-motion-and-the-legal-standard-for-review#:~:text=California's%20128.7%20motion%20is%20a,filed%20for%20an%20improper%20purpose.