Cell Tower reception

I am president of the Rio Hondo Ranch POA subdivision five miles West of Tarpley, Texas off of Hwy. 470. We have 2,000 acres with all 175 parcels owned. To have cell phone reception we must have AT&T. I am told that there is a cell tower within three miles of our location. I need to speak with someone that controls tower signals. we are in the hills and signal goes over the top of our subdivision. need to have the signal directed downward so we can have usage in the subdivision. Who do I contact and how?

Thank you.