Once a tenant (unfairly) threatens rent, your relationship with them is over.

They refused to call a real heating/a/c company, until I threatened to report them for providing inhabitable housing due to lack of heat. 

Yeah, I was thinking that threatening the mama of a bunch of bikers probably wouldn't go well.  

And, if you ever end up in court, it will be apparent to the judge that you were trying to avoid court, and were dealing very openly with the tenant, including letting them know of their rights and remedies.Tenants who start acting in a threatening way regarding habitability issues, often just want out of the lease, but they won't ask straight out if you'll let them out of the lease, or they don't want to pay the termination fee.  

If they won't let you then you need to threaten to sue.

If so you can play hardball and threaten not to close if they don't reduce the purchase to a number equal to the originally agreeded upon price.Remember sellers want to sell.

I am not the only one that didn’t have a great experience or that he has threatened.

Even though it's not my problem, I called the insurance company claims department who advised they got 3 threatening letters and phone calls from the lawyer who most likely work on a contingency basis, and that's all he'll do in these cases and drop the matter.

We have another unit (Duplex) where we inherited the tenants and one of them has been nothing but aces and of course the other one is nothing but problems and hasn't paid rent since October 2020 and that's just the beginning, has chased away our contractors, threatened our property management & the other tenants we've been to court to get them evicted and have lost on two (2) separate occasions.

At the local level, they know that every vote counts, and that voters have friends and neighbors that they talk to ... light a fire under them, they'll know the right person to threaten .