Can a contractor file a Constitutional Lien against my property?

Back in December of 2021, a water purification company came and installed a system on my house for me to "Try before I buy". The next day, I informed my sales rep that I did not want to move forward with the system, and would like it removed. He said that he would take care of it. No contract was ever signed, and nothing was agreed too. The company then waited over a month to contact me about removing the system. In their own contract, it says that they have 20 days from the time you cancel to remove the system, otherwise the property owner retains the rights to the system. When they called to schedule the removal, I informed them of their violation of this clause. They then discontinued communication with me. I reached out to the sales rep, and he agreed that they did not perform, and that I had the right to retain the system. Now, over 8 months later, I am receiving a notice from their attorney saying they are filing a Constitutional Mechanic Lien against my home, and immediately foreclosing on it? Do they actually have a right to do this? Especially with it being a homestead property, and there never being any agreement made?