I hired a contractor who bid the job at $50/hr. He informed me that he needed help and hired his friend to help. The bill I received charged 29.5 hours for both the contractor and his friend. I told the contractor I did not agree to pay his employee $50/hr and that the contractor is responsible to pay his employee. Contractor said his help is an independent contractor, which I said he was not authorized to hire an IC without my approval and I was not provided a certificate of insurance for his help. The contractor said his help was working under his GL insurance. There is no contract and the contractor is still billing me $1475 for his help. Based on Colorado law, i am understanding correctly that because there is no written contract and the cost was over $500 the contractor cannot file a lien on my property?