OP: based on what you say, you clearly deserve to get the GPU back. Even if it did get "used" on the short leg, it should not have been used, and therefore it's not your fault that it was.

With that in mind, your challenge is to get through to somebody who understands the situation (and, in particular, is not under the impression that you could not have done what you did in fact do when you applied it only to one leg!), and who has the power to fix it.

1. Try MPSC as suggested above.
2. Try emailing 1KVoice.
3. Send a polite PM to UA Insider here on FT. (I haven't done this in a year or so, and I think they've gotten less involved, but if you can get their attention, they know from the start that you're not an idiot).