Not wanting to sound harsh, but if you missed the option of letter of explanation and that business cards are needed the chances are you missed something else too... I had an application sent back last year as i forgot a copy of mydegree certificate (i had my eca...).
Essentially they are sticklers for details - you might be ok without business cards - with mine I only have a generic (no name) for my current employer, and only one from previous employers...