My first property and already a possible legal issue

[Brent Rogers]

I bought the property in January.  I immediately had problem with the heat in the HVAC.  I spent $2500 on a new furnace.  The property has two HVAC units that heat and cool the two sides of the house as it once was a duplex.  I used a company that is not the one recommended by my property mgmt company only because the other unit was installed by this company in 2014 and still under parts and labor warranty.  Big mistake.  I am now having A/C problems.  With both systems set on 72 one side cools to 72 and the other hits 80.  Given both systems are under complete warranty I called this company in to fix.  I traveled to the house and was present.  They charged me $140 for visit and diagnosis.  The repair guy walked in, looked at the return vent and said "there is your problem".  The return ducts were really dirty and needed duct cleaning.  I asked how much.  $800.  I said wow and are you sure this is the problem because I would hate to pay that kind of money and it not be the fix.  He said he was "absolutely sure" and never looked under the house.  Ducts were cleaned and it had zero impact. I called the repair guy.  Repair guy came back out.  I was not there this time as I am out of town owner.  I called him after he left from second visit.  He threw around a number of reasons why it might not be cooling but basically said the systems were running fine and he didn't know why it wasn't cooling.  He also denied ever telling me cleaning the ducts would fix the problem.  I called the owner.  He talked to the repair guy.  He called me back.  He sided with the repair guy and demands payment for the duct cleaning after I told him I am not paying.  He says he is putting a lien on my house.

A tenant was standing there when the repair guy told me he knew for sure this would fix it so I have a witness.  I told the owner I will see him in small claims court.

I do not want to go legal route unless I have to but what course is best:

1) pay the $800 and part ways even though my units are still under warranty

2) wait and see if he follows thru and then lawyer up

3) get a lawyer to send him a pre-emptive type of letter

4) something else

I hope to own more rentals but hope this is not indicative of things to come.