So disappointed in Xfinity Mobile

Here's my experience.

Three weeks ago I met a woman named "June" at  Xfinity Mobile telephone (I was calling for a separate issue).   She offered a really great deal to switch over from our 6 lines at AT&T to Xfinity Mobile.

The deal we agreed to was:  6 lines for $160/month plus a $100 gift card for each line after 90 days.   Having been on ATT&T for many years now, I decided to try to switch one line to see how the new service was.  She agreed to call me back at 10 am 2 weeks later to see how it went.

As promised, she called me back earlier this week.  She now had an even better deal for me.  The same 6 lines for $160 but now it was a $200 visa card after 90 days.  The service was fine where we live.  We moved over two lines that morning.  I needed to pay the other lines off, so she agreed to call me at 10 am this morning.

This morning she calls at 10, and we begin transferring the remaining three lines.  The first two lines go very smoothly, and at that time we have 5 lines transferred over.  One line to go.

She then comes back to me with an "Oh, we can't transfer the 6th line".  She says it's not possible.

So now I'm stuck with 5 lines at Xfinity and 1 line at AT&T which is going to cost me way more money just having 1 line.  

I've tried calling back and was actually on hold to speak with a "supervisor" but the call was cut off abruptly, and no one called me back.  So I had to start the very long and grueling process over.   I tried again and now am told no supervisor is available, and they can't add a 6th line.  

If I had known I could only add 5 lines from the start, I wouldn't have done this deal.  We have 6 lines, and that was what our deal was for.  We had an agreement, Comcast did not honor it, and now I'm left figuring out what to do.   I've spent hours on this today.