[icepush]

If you are in the US you can look up their official service address through the secretary of state for the state that you will be filing the lawsuit in. There is never a need for them to specifically provide you an official address.

[qingcharles]

And if you're filing a state case, and you know which county they are in, call the Sheriff. Every Sheriff's office deals with legal service on a routine basis. I've paid the Sheriff many times for serving complaints.