They were going after money they actually had no right to in the first place. They sent my roommate and I each a bill and then 5 months later we were getting calls collection agencies. What happened in this case, as what I would guess is happening in yours, is that the rental agency started with collections agencies.
You'll receive your check once all of your financial aid, including supplemental forms of financing like ParentPLUS Loans, has posted to your account. In most cases, this occurs within 14 days of the start of classes for the semester. However, first-time student borrowers may experience a delay of up to a month after the official beginning of the semester. In all cases, refunds won't be issued for classes dropped after the drop deadline.
Any remainder of grant aid will be paid to the student. The student will be notified within 30 days of the date of determination of withdrawal of the post-withdrawal disbursement. Student has 14 days from the date of notification to respond to college. A refund will be sent within 45 days of the date that the college determined that the student withdrew.