I actually have the same question. It's going to be impossible for me to pay the bill by August 15th because of reasons too complicated and boring to explain. While browsing through the billing website i read i could be dropped from all the classes and my registration blocked. If this happens, needless to say, i'm in a lot of trouble. I'll probably call them tomorrow and explain my situation and see if i can sort this out. I'll let you know how it went.