Legal Question in Personal Injury in California

Service by mail is not effective, unless you enclose an acknowledgment of receipt *and* the defendant fills out the notice and returns it to you.

But even if the person who helps you could serve the papers by mail, he would still have to provide an address on the proof of service. If your volunteer is unwilling to do that, get someone else.

Use a professional process server. For that matter, use a professional lawyer.

www.onelegal.com They're not very good at service of process in my experience, but they eventually get the job done if you give them a good address, and if you are web savy they are easy to use. Otherwise, look in the phone book for a service of process company.