Bad customer service and passing the buck

I would like to express my frustration with this company who does not really take people serious even when they billing your hard earned money for NO SERVICE AT ALL, I cancel their service about two years ago and for some strange reasons I was still been billed with no air time being sent to me and since then I received numerous reference numbers and every time I call the manager who can give me answers is on leave REALLY so if the manager is on leave every thing STOPS???