Should we pay college tuition bill for classes which student was not aware she was eligible to attend and did not attend? What might the consequences be for non-payment?

Looking for advice from someone who has experience with college tuition billing or having had a similar experience. My daughter signed up for college classes but due to a letter saying she was on academic probation, she wrongly assumed she was not eligible to attend them. She did not go to the classes but has recived a bill for the tuition balance (around $3000). She appealed but the appeal has been denied. If the bill is not paid I am wondering what the consequences might be and if they will resort to using a collection agency. Any insight is appreciated.