Adding more than 5 lines to Xfinity Mobile Account (continue)

Previous link, closed???!  Adding more than 5 lines to Xfinity Mobile Account | Xfinity Community Forum 

So I'll continue with this because it is definitely a bigger issue than their claim of "up to 10 lines" 

I'm a Xfinity Triple Play customer (Internet, phone, TV) +5years, +816 credit score,  Currently have 5 lines (self, wife, son, mom, dad) are on my plan and need to add an additional line.

Xfinity advertising up to 10 lines if so, why I can't add a line for my daughter?  You closed the previous thread and are misleading us.   Give me a shout Xfinity, I want to add line as Christmas present.