I just callled for an update on my gift card and was told that due the "huge unexpected response" from this promotion, the last of the gift cards should now be received by APRIL 1st.
When I contacted them in the middle of February, they reported March 1st.
Oh well, I'm confident that it will come eventually. I'm just glad I requested delivery confirmation for my letter when I originally sent it. It will prevent them from claiming they never received it...