This is a great question to ask the financial aid office at the school.
If the transcripts that they were waiting for were part of a requirement to enroll, then never receiving it would have made you ineligible for enrollment, which means you would not be responsible for charges in most cases. However, if that is not a case or your signed and enrollment contract which states that you are financial responsible, then you may be. Contact the school and they should be able to answer your questions.
I am a financial aid professional and I have started a financial aid blog as a project for a college course. Please check out the link below to read more of my insights into financial aid which you may find extremely helpful.http://financialaidwritings.blogspot.com/