Was I served properly in my California small claims case?

This is worth verifying rather than assuming. Small claims has its own specific service rules, separate from general civil procedure, requiring that you be served at least 15 days before the hearing date if you're within the county, or 20 days if you're outside it.

Defective service, meaning the plaintiff didn't follow these rules correctly, is a legitimate defense you can raise. Realistically, though, successfully raising it usually results in the court granting a new hearing date with proper service completed, rather than dismissing the plaintiff's case entirely.