There are two types of overpayment, a loan overpayment and a grant/bursary overpayment.
A loan overpayment exists when you have received more loans than you should have. This may occur because your circumstances have changed (e.g., change in course load, change in the amount of money you earned before you started school or while you were in school).
You are not required to repay your first loan overpayment. If you receive a second overpayment, you must repay the second overpayment in order to be eligible for further student aid.
A grant/bursary overpayment exists when you receive more bursary or grant funding that you should have. You must repay a grant/bursary overpayment to be eligible for further student aid.