Contacting 343 about account questions

Anyone know of the preferred method to contact 343 about Waypoint and Halo 4 account related questions?

One question I hope someone knows the answer to is what does the “Last Seen” date/time stamp mean when you click on the Friend List in the top right of Halo 4 Waypoint? A friend said he saw my last seen stamps posted in the morning and early afternoon last week and it was a day where I didn’t even turn on my Xbox until late afternoon. Is it related to logging into Waypoint? Kind of concerned since I’d like to know exactly what 343 is tracking.