My question involves collection proceedings in the State of: California

A little while back, a summons was delivered to my parents house, my elderly non english speaking mother accepted and was forgotton.

Later another summons was delivered to the building where I work. I was not in the office and the person bearing the summons was not given access and left it at the security desk. It has since disappeared.

Are these valid as I was never in personal receipt of the document?

Should I follow up on these summons?