I used to have a bunch of backdoor numbers for Verizon that I would share here, but they're all gone now. Every time a rep. would get suspicious of me asking questions about an account, they would call me back and their direct line would show up on my caller ID. I had about 10 different numbers from 3 different call centers. They were awesome, because when I called on them, they couldn't get my phone number. But one day, about 2 years ago, they just all stopped working. No idea why. I cried for days.