It caused lots of stress and I had to hire an attorney to get involved.

If it does not get enough airflow it will run hot which can shorten the lifespan of the component or even cause it to crack from too much heat. 

Can they still claim that they don't have to pay anything because I have an illegal tenant in the basement (even if he is not the cause)?

If they are good tenants who take care of your property, pay on time, and you expect them to remain longer term tenants then I would do my best to try to work the issue at amicably without causing any spite.  

I checked your account and I see the issue you experienced and apologize for anything caused by something on our end. 

Buying a luxury on credit often causes a person to eventually resent that luxury because the debt becomes a financial burden. 16th amendment in 1913 income tax became permeant.

Range Stove Top - GAS (if possible) but if not, then COIL (Less easily damaged and less costly to repair than Glass and I personally prefer it)Oven - NOT SELF CLEANING  (We experienced twice when the self cleaning feature was used and cause severe mechanical failure, requiring replacement of the entire range.

. - I've read a lot about NACA requirements of attending classes, volunteering for their cause, etc.

What was it caused by?

Just cause they are negative doesnt mean the risks are not real.