I don't know why someone at WHQ promised you that you'd clear ahead of UGS. AFAIK, there is no way they can override the auto-DM list without actually opening a seat and putting you in it in the same transaction.

I think that whoever you talked to originally made a promise that they couldn't possibly keep.

When your friend cancelled, the first person on the DM list was cleared by the computer. As we now know, that most certainly wasn't you.

I'd ask for the SWU back, but that in itself may be a long shot.