Who Is Reliant Inc. And How Can They Reduce Our Windstream Phone Rates?

Received a call from company identifying themselves as Reliant Inc., they said they were able to reduce our phone rates through Windstream if we were to sign up with them.  They indicated that we were not making enough phone calls through windstream to reduce our rates directly through them.  Who are they & how are they able to get our phone usage records? They said they were not affiliated with Windstream directly.  How can they reduce our rates?