Adding more than 5 lines to Xfinity Mobile Account

So, I have been trying to add a 6th line to my account with no success. Tried in person and over the phone and still nobody has been able to help.

The site says that for "Existing Customers" you can have up to 10 lines. I was originally told that I had to wait until the first bill showed up. Then to wait 2 more weeks. Now I already got my second bill and I am half way toward my thrid month. Is that enough for being an "existing customer"?

I have had Xfinity Internet and Cable for almost 2 years already and credit score is not a problem, so I am not sure what else is needed for being able to add an extra line. I moved to Xfinity Mobile when I was told I was going to be able to transfer all the lines from the previous carrier. 

Anyone else having this issue? 

Thanks