Need a PTR record

You have to call Comcast Business Support @ 1-800-391-3000 so they can do an account verification check to make sure you are authorized to make the change request and to create a case/ticket for the request. The changes are usually made within 24 hours and they will email or call you to follow up.

It can be tedious but it helps makes sure cyber-criminals don't have yet another tool in their arsenal.