Postgradute loan

Hi,

I have recently updated my change of circumstances and notified student finance, and my application was rejected, stating that they require further evidence. The reason for changing circumstances is that my postgraduate course starts on the 9th of January instead of October, as I previously applied for that date. I haven't received the letter yet of what further evidence student finance needs. Can you help?
I don't understand why it was rejected after I presented all the evidence they needed for my first application.