A Texas real estate rivalry led to a lawsuit against craigslist for trademark infringement, even though its users were responsible for the postings.

As reported by MediaPost, First Call Properties alleges that rival real estate company AAA Apartment Locating posted ads on craigslist using the phrases “first call,” “call first” and “call us first,” claiming that this was done with the intent of confusing consumers.

First Call also claimed that craigslist knew about AAA’s actions but failed to stop them.

First Call named craigslist, AAA and two individuals as defendants in the lawsuit, which was transferred to federal court in the southern district of Texas late last week, MediaPost reported.