Overall I have had the best luck with sprint.. very rarely do I have to contact customer service, but it has happened, and they do seem to have a great deal of difficulty fixing a bill.
I get service about anywhere, limited problems. I cant say the same about other carriers in the past. I wont use verizon or cell one if its available in an area. My family has had their share of issues with the metro phone company(frgot who it is now) with cell phones.
I would go strait to the managers at sprint and write down names.. deal with your issues once and for all and get it strait. I suspect your problems will go away once you dont have to hassle with customer service.