i don't think it's going to work. google had gvoice for years and marketed it with free phone calls and voicemails, and it didn't take off. i had a similar project 5~6 years ago, which fell apart. my conclusion is that free call is not attractive at all to general public. if you are competing again telcomms (excluding MIM apps), you need a product that is 10x better, and "free" is not a magic word. or, find your niche! (e.g. crowdfunding project funders, consider my disapproved kickstarter project: https://www.kickstarter.com/projects/1015114671/1150193072?t...)
Look, if your service is useful enough, it will get traction even if you have no website to boot. That has been the reality of supply and demand since ages.
good luck!