How do I go about foreclosing on a property I have a lien on?

I did work on a home for a investor, on an investment property. They did additional work that I was never paid for. Upon doing title search on the home, the owner is not the investor I have the contact with. It is titled in a investment company that employed these individuals to rehab the house and split the profit. I files I lien on the property, sent certified notice to the investor I had the contract with, as well as the company the title listed. They attempted to sell later, but the seller backed out due to the lien. I need to know how to go about foreclosing on the property. It is empty and not homesteaded.