my employer is Head quartered in New Jersey They have placed me to work for their client on a contract basis in California. I wanted to be a permanent employee of my employer, when I informed this to my employer they said they can employ me only if I acce

I am a H1b status person with a principal employer in New Jersey. I got a contract job on my own thru a vendor and their placement company, the company is also Head quartered in New Jersey They have placed me to work for their client on a contract basis in California. I wanted to be a permanent employee of my placement company, when I informed this to my placement company they said they can employ me only if I accept 60% of what I was earning as a contractor. This is not agreeable to me and I found out there is another placement firm who provides contract work to the same client . The client is very satisfied with my performance during the last two years.. Now I wish to know that if I work for the same client thru the new placement firm then can the first placement firm bring non compete in play