Originally Posted by Duke787

This sounds like a different situation than the OP. It sounds like you did a Cash + Miles upgrade and it cleared the first leg but did not clear the second leg (while the OP took a pure cash buy-up offer after purchase). Per the terms of UA cash and miles upgrade, you are entitled to a full refund if the IAH - GIG portion never clears, even if you ride in F for the YYC - IAH leg. Basically if you do an MUA upgrade and it doesn't clear into Polaris for the international premium leg, it's not considered used even if you cleared on the connecting domestic leg.

It's actually one of the few consumer friendly policies UA has:

However, if your travel includes requested upgrades to United PolarisSM business class or United Polaris first class, and none of the international premium segments are upgraded, then your MileagePlus Upgrade Award will not be considered used, even if you are upgraded to United FirstŪ or United BusinessŪ on another segment. In these instances, we will fully redeposit your miles and co-pay. When applicable, these refunds will occur automatically seven to 10 days after travel.

If you don't clear IAH - GIG you'll eventually get your points and money back and have gotten a free F upgrade from YYC.

Link: https://www.united.com/web/en-US/con...rade-faqs.aspx