Blacklisted IP for former employee/customer

I’m a retired Comcast employee that still has a Comcast.net email I use. Last two weeks I have had an issue downloading email to my Apple Mail app.i’m getting the error that my IP address is temp blacklisted. Try later. I’ve tried deleting acct and re-adding it to my mail app, changing password and still have the same issue. I’ve even used app in different location which would have been a different IP address. Still not working. Of course I’m no longer in a  omcast area and no longer have an acct number so I can’t get help via customer support phone. How do I get this to work again?