Once memberships are paid off in the NSDA system, Tabroom should update within a few hours. If you're still missing students, they likely either aren't linked (click "NSDA Points Competitors Connections" on the right side of your Competitors roster), or Tabroom thinks they're ineligible for some reason. If you have a "Missing Students?" button below the entry dropdowns, try clicking that for a screen with more info.
Otherwise, email firstname.lastname@example.org with the details.