There's a good chance the issue(s) you face has already been discussed and answered.Ask questions in the appropriate forum.

While the heater issue adds extra stress, addressing it promptly will protect you from further fines and penalties.

One more thing I should address:  Installing cameras inside of a residence with other tenants can be a HUGE legal violation.  

The "due on sale" clause (DoSC) obligates the seller to notify the lender if the property is sold.Failing to do so would place the seller in violation of this agreement, giving the lender the right to accelerate the loan.But no laws are being broken here.So, subto is neither legal nor illegal.Second, it only works because most lenders are more interested in receiving payments than in invoking the DoSC clause and foreclosing on the property.But, it can work, provided seller and buyer are both on board and the proper process is followed.

So, to try to go a legal route because they might have fixed something a little over the limit isn't going to work.You will have to face that you selected someone that was not the right fit and be more hands on. 

Bill her for the service call if they are no issues with furnace.

There's a good chance the issue(s) you face has already been discussed and answered.Ask questions in the appropriate forum.

Especially in an area where it’s legal.

Again, this is with commercial/investment property; owner occupied or consumer loans may have legal issues rendering this technique non applicable.  

There's a good chance the issue(s) you face has already been discussed and answered.Ask questions in the appropriate forum.