How to Evict non-paying RSO tenant that keeps complaining to City

[Sean Raven]

I have a non-paying tenant in Los Angeles. Rent is about $3,000; it's a nice yet old condo (70's). UNIT IS RENT CONTROLLED. We've been fixing things in the condo almost from day one since tenant complains about petty things (e.g. one hole on a screen on a window). She has taken it so far to complain to City of LA Dept of housing and is calling health department now (in short "we want revenge" kind of mentality, but in reality, they don't have the money to pay). Now she has stopped paying rent completely. Has been there for 2 months total.

I know that Unlawful Detainer is the way to go. Need lawyers to help with the matter from day one since I'm pretty sure she will drag us up to jury etc to waste time and will involve an ambulance-chaser-type tenant defense lawyer.

Just to make things worst: I forgot to register with RSO and now I'm not sure if we have to serve a 3-day notice or not?

Any advice / strategy is welcome.