Sbc won't let go?

Hi, i had sbc phone service for a while. I rarely use my phone and my phone bill is always 65.00 to 80.00 bucks. So i switched to Time Warner since the first day of service, I always got calls at 12:30 and 4: 30 am daily. A month later i switched back to sbc problem solve. My bill is still 60 to 80dollars I switched again and guess what? My phone started ringing at 12:30 and 4:30 again does anyone has the same problem. Can someone help? Thanks