You're having an issue with 20 minutes on hold as a silver with United? Try over 1 hour hold times for a UA *G calling Air Canada for a simple request that cannot be done online because the AC website is pretty poor
Yes, United does have seat map issues from time to time. This wasn't some benefit being taken away from silvers, but rather a temporary issue on United's side. Let this one slide and see what happens next week if you're actually traveling weekly. They're not out to get you.
-RM