Deadline for interview: 10/19, i sent mine 10/31, i was just called for one today...?

<p>I'm confused</p>

<p>duke says i need to submit my supplement or commonapp by 10/19</p>

<p>i sent mine 12 days later</p>

<p>why was i still called up for an interview</p>

<p>also, how should i prep for this? What is duke's interview like?</p>