The subdivision I live in has had decent service for both voice and data quality until a new tower went up a couple of months ago.  This new tower is less than a half bird mile from my home and directly across the street from the subdivision.  It was placed in Cheatham Elementary School parking lot in Marietta.   Since the construction was completed service is horrible.  Doesn't matter if you are Sprint or Verizon, don't know about ATT but I assume the same with them.
None of the tower apps show the tower as in existence. 
How do you report such a problem to the vendors?
Doing historical searches for people who have similar problems, it seems nothing is ever resolved.  You end up being told you live too close to the tower or it is some other RF interference.