As your first step in defending against the eviction, you can file a motion to quash, which normally says that you have not been properly served with the summons and complaint. However, even if you have been properly served, you can still file a "Delta" motion to quash. It says that they can't use the 5-day summons because there is some technical defect in the Complaint, making the 5-day summons reserved only for evictions the improper form to use.
A Delta motion requires substantially more review and research than for a normal motion, where the only issue. is.t proper service. In the Delta motion, you are attacking technical defects in the Complaint, which does required some research and investigation. You still get at least the 3 weeks from filing, and probably more time in your next step, the Petition for Writ of Mandate.