We just had new AC Unit installed in our condo & paid $3500, wasn't installed properly, had to be fixed once already - no fee. Still under warranty, the air flow was not good since installed. Made appointment for tech to come out and was assured there is no charge, since the unit is still under warranty. Problem was not fixed, we put in our new lighter filter in hope it will help while the tech was here(the current filter was less then 30 days in the unit) & we are being charged $79 for pretty much changing a filter that didn't need to be even changed. We don't want to pay the fee & Contractor is threatening us to put lien on our condo. There is nothing in writing, just assurance over the phone there won't be a charge. Now he claims it cost him money for gas to come out no matter what. Two completely different stories. Please can you advise us what are our rights? Can they sue us & put lien on our condo? Do we have to pay the fee? It's not the cost but the principle, dishonesty, threats, insults the way they treat us and nothing was accomplished. Thank you!