Need to fix pointer record for static IP

Please let me know how to update a pointer record. Have been on the phone for an hour with Vanessa who says that Comcast employees are not authorized to change pointer records.

She tried to point me to mmmc.comcastbusiness.net/menandmice where we are supposedly able to do it ourselves. But that site is not accessible.

Please let me know how I can update a pointer record for one of our Comcast static IPs.