Can I do anything after i've missed the deadline for a preliminary?
Yes, still send a preliminary notice. In California, preliminary notices have what we refer to as sliding protection. Meaning that a late notice will still secure lien rights for any labor and/or materials furnished within the 20 days preceding the late notice, and everything thereafter. It's always better to secure some lien rights as opposed to none.
If, however, it has been longer than 20 days since any labor or materials were furnished by you, then lien rights will no longer be available. Here are some additional resources that may prove helpful: