why can't I access another class while waiting for a shipment

I just finished my Fitness class and found that my next class has a shipment that I need before I can do it.  When checking the shipment history it was just sent yesterday and can take up to 10 days!  I tried to access my next class and I'm not able to   Now I've fallen behind my schedule and was hoping to get right on the next class to maybe get caught up