Ditto. I nabbed roughly 700 points since I signed up and none of them are showing on that challenge. :/
i'm pretty sure the number of points you've acquired since signing up isn't supposed
to show anywhere. that's one of the lame things about the contest...have to track on your own how many you've earned since that date and then notify them when you think you're finished. if you've gotten enough points, they'll check it out and give you the appropriate prize. it would be really helpful if they at east kept track of your starting gamerscore at the time you signed up. it's also not clear if all points gained between the official contests dates are counted, or only those obtained after the date you actually signed up. looking at my achievements, it looks like i've only gained about 150 points since i signed up on 2/20...the earliest day i could actually access the site. that total jumps to 465 if you count what i've gotten since 2/12, so who knows where i really am in regard to the contest.
on the upside, i did get an e-mail a couple days ago stating that they've lengthened the contest to run until 4/22...an extra ten days to meet your goal.