Need to file formal complaint

I need to file a formal complaint regarding an employee interaction at an Xfinity retail store, and I would like the complaint documented and escalated beyond the store-level response to the appropriate district, regional, or corporate management team responsible for the Xfinity store at 5611 Pacific Ave, Unit 100, Stockton, CA 95207.

After my wife filed our complaint by phone, she received a call from a supervisor at that store. Unfortunately, we do not feel that the call helped resolve our concerns or provided a meaningful path forward. We specifically asked for the store manager and supervisor did not even know the manager’s name.