Verify the drops are claimed on Twitch and then head to https://www.bungie.net/7/en/Codes/Partners. On that page, press 'refresh' and your missing drops should appear on the list. If they do, then check your collections for emblems otherwise check the Special Deliveries kiosk for ships/shaders etc. If they don't, contact Twitch support to see if there are any issues with the drops (ie they've expired or Twitch is having server issues). If there aren't any issues then try refreshing again after a short while.