VOIP and Internet charges

Amy wrote to me to ask about Internet and VOIP charges. I don’t know much about US telecommunication rules, so I’m putting her question up for my readers:

I have a general question – we are an IT company in Vienna, VA using shared office space, but with a very old PBX which will not allow us much flexibility. We want to use VOIP., instead, and ride over our internet connection BUT the owners of the building insist on charging us a fee (fine!) of $50 per phone (3) to do this — isn’;t this double billing, since we are already paying for the bandwidth for our internet? Anything in our FCC rules which prohibit this?

I suspect the fee is there because VOIP increases bandwidth usage. Can any of you help answer Amy’s question?