Zillow and mega-brokerage Compass are battling it out over where real estate agents can list homes for sale. Homebuyers are stuck in the middle.

Real estate brokerage company Compass has filed a lawsuit against Zillow, claiming the popular real estate website is refusing to accept home listings for properties that have been initially advertised for sale elsewhere.

Compass is suing Zillow over what it calls the "Zillow ban," a new rule that the real estate brokerage firm claims is meant to control home listings and crush the home search competition.