If you accepted the Challenge (i.e. didn't have it disabled), you should've got the money.
Double is nice, but I have a feeling that at least for me it still doesn't quite cut it. As HIO on long holes are extremely rare (much more so than prize amounts I guess) and even making it within 1 ft is less than 1/10 event...
It would be much nicer if WGT would say that they use at least say 80% of entry prize money for the payouts - then we'd know we're not being duped.