Does Videotron have a greylist of user IP addresses?

Today I telephoned Videotron technical support for the 4th time in 3 weeks and this time I asked about the existence of a greylist at Videotron that I might be on. I was told that the 6 minute delay for my outgoing email is due to my email passing through a central agency not belonging to Videotron which blocks or delays emails based on the reputation of the source IP address.

Videotron Technical support sent me a link to the Cisco TalosIntelligence website. I assume that I got this link because Cisco is a supplier of some of Videotron’s email server infrastructure. According to the Cisco website, my IP address has a status called “neutral”, instead of being either “good” or “bad”.

I opened a ticket at Cisco asking that I be removed from their greylist in case they had one. The Cisco robot, which apparently doesn’t read text written by a human being, automatically answered me saying it could not process my ticket because my "neutral" status is already good enough to allow my emails to go through.

I also learned by discussing my situation on a forum devoted to questions about IP address blacklists, that there does not exist a central facility through which all the emails in the world go through, including the emails that I send to myself. The forum moderator told me that it is Videotron alone, or in collaboration with a partner (like Cisco), who has created a Videotron greylist and Videotron is uniquely responsible for delaying my emails based on my IP address.

How can I appeal my case again to Videotron technical support when the 4 experts at Videotron appear to not know if their own infrastructure has an internal greylist or not?

Has anyone succeeded in getting Videotron to replace their home gateway IP address with a different one?