Messages from Assistant saying my home needs technician appointment

I keep getting notifications stating there is an issue affecting my Xfinity Internet service. Notes say I need to set up an appointment to have a technician come to my home, get access to home to fix it.  Doesn't say what the problem is and gives no realistic indication of what they are actually looking for. Is this a scam and, if not, what's the problem before I let someone into my home?