I then explained to him that he does not have a contingency, and he is breaching our contract by attempting to cancel simply bc he was offended that I asked for a repair credit.

I have had at least 4 or 5 attempted scams from guests off of VRBO but never the other platform. 

Others have ignored our property manager's attempts to reach out and work with them, and that makes it much more difficult to try to help them. 

I IMMEDIATELY non-renew any tenant that makes a threat (direct or veiled) in an attempt to manipulate.

Maybe the Landlord attempted renting on their own and may have oversold the property features and maintenance. 

They do not even write me up for the legit issue because they attempted the extortion and know they can get in trouble.

If the tenant attempts to contact you about this, forward it to the insurance company or their attorney.

I would want to see a list of applications with dates and denials.Point 2: Not much help here unless you are in a very expensive rental market.Point 3: I would need to see a copy of a letter from employer stating they had reduced hours and that was due to C-19.Point 4: If they have done anything like buy/lease a new car, take a vacation, bought a major non-essential household item like a TV, or even gone out to eat regularly at restaurants in the past year I think you would have a very good claim that they are not attempting to pay you partial payments

So I hired a plumber and he attempted to repair it with boiler sealer but it only made it worse as the boiler started to leak heavily.We have decided to replace the whole boiler and was told may take 1 to 3 weeks as all the boiler are sold out.

Also, would multiple pre-approval attempts hurt my credit score?