Roxanne Isley at AT&T lied about reducing my phone bill if I'd add another line Internet

I'm really not the kind of person to be writing something like this, but this was an especially egregious situation that I feel needs to be addressed. I'd originally called into AT&T about some misunderstandings regarding my bill and what an AT&T store had told me my bill would be reduced to, since I hadn't seen it decrease per their guidance when I moved over my phone lines.

I talked to a rep there, really nice, who took some time to try to understand why the store rep may have promised what they did. They asked me a little about my business and told me they'd try to see what they could do, and they asked if they could save me money while adding another line would I be interested. I was skeptical because of my experience so far, so they brought their manager Roxanne Isley on the line (I only know her name because she sent me an email later). At the end of the day, she told me they could cut my bill in half while adding the new line, and sent me an email backing it up.

I waited 3 months, 4 months, nothing happened. The bill was even higher than before, because of the extra line of course. I called in a few times and couldn't get anywhere. I emailed Roxanne several times and she never replied or responded.

At this point I don't know what to do, but I feel AT&T could do a better job of keeping their employees ethical.