Recently I had laminate flooring installed throughout the house. I gave the company a downpayment on the flooring the day we ordered the material, I was to give them another check the day the flooring arrived, balance was to be on completion of a satifactory installation.

From the start we had problems with the company, from the day the material was to arrive to the day the workers were to start. When the job was almost completed, we could not take anymore time off work, so they were to come at 4:00pm to finish in the evening, they never arrived, no the next day. We made several phone calls. An finally 4 days later my husband and I decided we need to finishe ourselves.

This meant purchasing items and removing some of the floor to fix. It still is not perfect.
We contacted them and say we would pay them only a portion of the balance. We had subtracted items purchased and payment to my husband for his work.

They refused and said they would put a lien on our home, they have never send us a bill, can they put a lien on house without our knowledge??

They can place a lien on your house; I do not know whether you get a formal notice or not, but 'all the world' is considered to have been notified when the lien is recorded at the courthouse. I didn't notice in which state you reside. Check this: "A mechanic's lien is a security interest in the title to property for the benefit of those who have supplied labor or materials that improve the property. The lien exists for both real property and personal property. In the realm of real property, it is called by various names, including, generically, construction lien. It is also called a materialman's lien or supplier's lien when referring to those supplying materials, a laborer's lien when referring to those supplying labor, and a design professional's lien when referring to architects or designers who contribute to a work of improvement."
Mechanic's lien - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Mechanic's_lien)