How to stop repeated text messages from xFinity

I keep receiving text messages saying "Reminder: Return your UNUSED xfinity equipment today to reduce your monthly bill...".   I am not leasing/renting any xfinity equipment.  I have been using my own equipment from day 1.  Also, when going to the URL in the text message it confirms that I do not have any xfinity equipment.  As such, why do I keep getting this text?  How can I make it stop?