You do not need to contact KCC, because the affidavit of support document only comes up during your interview date, hence at the embassy. Not sure when your interview date is, but you can always ask your sponsor to send you the I-134. Additionally, it has being reported that the embassy on many occaison to take I-864 in lieu of the I-134. Therefore do not panic. You never know you may not even be ask for an sponsor, depending on your own net worth.