Verizon's $120 labor charge

I wanted to set up a phone service with Verizon. I paid for the set up fee which was included with my first month bill. Now, the second month bill is showing that I owe them another $120 as a labor charge. I tried to contact Verizon to find out the reason of this charge. They are saying that they didn't do anything but came to my business location to see the phone service was working OK. What kind of a crap is that? I am asking for a paperwork showing that I received a service for any reason. They don't have no paperwork no nothing. How can Verizon charge me $120 without a proof of a service????