Sorry, OP, for your bad experience. It truly sucks to fly in Y after having expected to fly in F! But then again, things like this happens, especially with UA and that as "loyal" customers of UA we are all aware of these customer-unfriendliness of UA. I think it's a shame that you lost your upgrade, but as most people on FT say, if you want to fly F, pay for F. When upgrading and waitlisted, always expect to fly Y.