It seems that this may be a "sort of cultural" issue: it works one day and not another.

I, too, signed up and did receive my number and pin via email. I then attempted to obtain their "distinguished client" card for $150 which gives you bonus miles when you fly C class. According to the web site this can be purchased at any Mexicana office. I went to the local one by the SFO airport where I spent 30 minuted while the 2 women in the office called all around to find out about it. They had no ide what I was talking about. I made them look it up on their own web site. The final outcome was that it was only available at any Mexicana office IN MEXICO. The web site does not say that.