When I changed the email on my mother's account about a week ago, I assumed it would take quite some time. I submitted the ticket and started watching a movie. When the movie was over I checked to see if there had been a reply yet and it turns out it was about 15 minutes later and they sent a text to verify her identity. Responded to the text about 2 hours after they sent it, and about 20 minutes later they responded and changed the email. So if you skip the 2-hour gap that was my fault, probably would have turned it around in about 20 minutes. That was during the day, sent around 1PMish eastern on a weekend.
It all likely comes down to work volume and perhaps a priority queue. Changing an email would likely fall lower than getting someone's service working.
