You know what happens when you assume

About a year ago, my brother and his fiancé allowed me to come kick it with them for a few months.  I got my own Xfinity account while I was there.  Understand, my birth name and her 'nickname' are spelt the same, different pronunciation.  'Nickname', not birth name and they aren't married yet, she got a whole different last name.  Well, xfinity just assumed we were the same person.  She found this out cause they started calling her non-stop about my bill. (I lost my job and got behind).  I log into my account today and it says 'Welcome... her birth name'.  What?  I never added her Info and she been trying to tell them this for months, we 2 different people, but they tell her i gotta take her info off my account.  Why I got to do it?  I didn't put it there, they did.  Assuming things.  I'm on hold right now, been 48 minutes this point agent not knowing what to do, trying to figure it out.  Sure they didn't train him for what to do if Xfinity assumes something and they wrong.  Agent finally came back on.  All he could tell me is ‘call this number’.  So I do and I put in my info and the automated just hangs up on me.  This can't be legal. Do I need to get a lawyer?