Digging up my lawn to provide U-verse service to my neighbor

An AT&T crew or service man was running a wire cable from my neighbors house across a portion of my lawn, across the street to an AT&T U-verse box.  I told the service man that I did not want the wire cable on my property nor did I want them to dig up my yard.  He stated that he just ran the wire connection and another crew would do the digging.  Who do I contact and how do I prevent AT&T from digging in my yard?