How do I contact the ATT subcontractor that destroyed my yard and fence while installing your lines in my yard.

Feb. 24 2 men cut our fence and proceeded to drive a big yellow machine through 200 ft of my rain soaked landscaped yard. We had no idea they were coming and no permission was given. The job was in regard to burying a line for our nextdoor neighbors service. Sedgwick ATT’s insurance company sent us a letter yesterday saying I had to contact the subcontractor! I have no idea who they were and neither does my neighbor. ATT hired and paid them so one would expect ATT to cover the damage. I am furious to say the least. Approximately 5000. In damage. I need help with this! My father is 90 and cannot physically do the work nor should he.