I got the same problem, I got an Iphone several months ago with a new phone number because I was keeping my old verizon phone and all I get is collection calls for the person who had the number before me.
I get calls from the Gas company, light company, Comcast, Directv Etc. Then you tell them your not the person they are looking for and the bill collectors don't believe you!
Only reason why I keep the number is because the last 4 digits of my phone number spell "DISH"