How do I stop the setup reminders on the top of my Samsung phone when I no longer a customer of Xfinity

I canceled Xfinity 6 months ago and yet I am still getting set up notifications on the top of my phone, not email or text, but on the top of my phone. I deleted all of the Xfinity apps, reset my restarted my phone, I've toggle the on and off of airplane mode for 30 seconds, I went to Wi-Fi and deleted any Xfinity connections, but I'm still getting those errors. When I spoke with customer service for samsung, they checked and solved them that's my phone is still connected to Comcast service system. When I call xfinity, because I'm no longer customer it doesn't recognize my phone number and I can't get through to anybody.