Get a line free* for a year with home internet

I signed up for home internet online and seen that they were running a promotion to get a line free for a year and I had XX amount of time to sign up. I opted to sign up and called customer service to ensure that it was set up through the promotion. Mobile line was established and I was told by the representative that I was to only pay taxes on the line roughly $3–$4 a month. Fast forward, I received my first bill of $97.93 for 2 lines. Immediately call customer service to be told that 1. That promotion didn’t exist & 2. They don’t give credits for the first month. Once I asked for a supervisor then all of a sudden the promotion did exist & he “fixed” my account to receive the promotion but would only be crediting me for the second line that’s not being used. When I asked to be emailed the terms & conditions stating that the 1st month is not free, I was told they can’t do such a thing. Xfinity mobile is proving to be a scam.