I guess you got the same email I did.
I got some email this morning reminding me about the rewards scheme, and completed the survey for the 250 points (having not done one in months). I'm currently showing as 4650 points, but that doesn't seem to include 250 from today's survey, so am pretty close to my first reward.
31/12/13 - MyAchievements – Legend Rebate - 400 Credits (Pending)
19/09/13 - Played New Game Release - 1,000 Credits (Pending)
02/09/13 - Completed September Survey - 250 Credits (Pending)
26/08/13 - Renewed 12-month Xbox Live Gold membership - 3,000 Credits (Pending)
Not sure what the "played new game" reward was in September. I guess I didn't play Forza enough for the reward (sounds about right - I probably only played about 2 hours). Must've played dozens of hours of COD in November - no reward there. I wonder if the month started when it came out on last gen platforms, because I'm sure I must have played well over ten hours in the first month after the game's release on xb1.
Fingers crossed for reward points soon for Rayman Legends, Thief, and Titanfall.