Valuation Vision The contract that they required me to sign states that they pay in net 30 days. They owe me from October and we are now in December! calsbad California

I was hired by this company as an Independent Contractor because I am a Realtor. This company provides their clients with BPOs (Broker Price Opinion) and CMAs (Comparative Market Analysis) of homes that are going into or have gone into Foreclosure for the BPO and possibly going to be sold (CMA). These jobs require a licensed real estate agent to complete by law. They are hired by banks and other agencies who need cheaper and faster means of getting an Appraisal. 

I have had several telephone conversations with them. The last one I had they stated that they were "behind" in paying but they are working on getting caught up.  The contract that they required me to sign states that they pay in net 30 days. They owe me from October and we are now in December!