Call It In
Just tried to apply two Copa GPUs to a UA itinerary online. I've successfully done this before, but the interface has changed and it didn't work this time - claimed fare class was ineligible (W fare).
Called Copa. First agent was exceptionally friendly but could not find my reservation through either Copa or UA. I was getting really nervous. He put me on hold to speak to a supervisor, and disconnected me instead.
Called back. Second Copa agent was a dream. One of the most pleasant cs reps I've ever dealt with. Got me quickly squared away with confirmed upgrades, no issues or all.