So our uni upgraded its grading and notification system, and it didn't notify me of a 70 point assignment until an hour before its due. I've gone to every class and the professor didn't mention the assignment at all. >:( No late work allowed and I checked the website every day.
Usually courses allow you to submit mitigating circumstances which allow you to submit work late. You should definitely speak to the head tutor for your course/year or one of the senior professors and ask for some advice. They're usually very helpful I found and have the answers you're looking for.