Tenant Noise Issue and Threat to Sue Landlord

[Chan K.]

Hi Team,

I am hoping to discuss and get some opinion on the following matter. 1) I have this one tenant, every time she/he calls, everything is emergency/urgent. For example, I got a call on the Holiday weekend at 6:30 PM reporting an emergency/urgent leak. I asked if it can be addressed on Tues, the tenant threat me that she/he will get their own plumber and deduct from my rent. I eventually managed to get my maintenance guy down there. He checked the leak, and it was a slow leak that occurred from a wax ring issue from the second floor. It seems to be there for about 1-week already. So obviously, it was not an emergency/urgent. We eventually fixed it on the Holiday (Monday) as the tenant on the second floor is finally home.
  2) Other tenants in the building have been telling me, and this morning I received a call complaining about tenant from 1) above due to loud noise generated by karaoke singing all the time in the weekday. I quickly sent out a text to the concern tenant to low or stop playing the karaoke. She/he allows to do such karaoke on Sat at 11 only. Then, her husband called me and screaming. This guy went off on me. Not normal - threatening to sue me if I kicked him out as he is on disability and I am causing him distress, and threatening to have the tenants who complain to talk to him (probably plan on beating them up or something). I told him that it is the building rule and I want to enforce it. He told me that he is not a kid why the heck am I doing rule .... blah screaming unprofessionally.
  So what are your thoughts? Let's discuss ...