If you are a sole proprietor who get a 1099 and you never set foot in CA then getting a 1099 from a client who is located in CA does not make it CA income ... this is not the same as if you were an employee who worked remotely for a CA company. Do not mix up the terms ... employee/employer and sub contractor/client as they have different rules. I would respond back saying that you did not work anytime in CA and none of the 1099 income is considered CA sourced.
