filing a complaint

Where do I go to file a complaint on the automated sysyem. The automated system constantly tells me that I am behind on payment. When I check with the xfinity store, they say that I am up to date and not delinquint on my cell phone bill.  The automates system shut off my cell phones 1 day before christmas for 4 days, I had checked with the xfinity store on my payments and they say that all payments are up to date, the xfinity store gets my cell phones turned back on. Since then the automated system calls my wifes cellphone demanding payment, and will not let me talk with a live agentwhen I ask for agent it starts over with making a payment if I try to force an agent call the automated system hangs up the phone call. I tried several times to contact agents on this matter by phone with no success only help I can get is at the xfinity store., but their hands are tied since they can not do anything towards the automated system.