If you withdraw from a class or from school before the withdrawal period ends (usually 60% of the term), you may have been due to at least a partial refund from the school. Sometimes this is paid to the student, and sometimes it is paid to the lender. If you (or your lender) did not get a refund that you were entitled to, you may qualify to have part of your loan discharged.
To calculate your refund, you need three things: the tuition, the school's published refund formula, and the percentage of the term that you completed. The school's published catalog for the term year should have the tuition and refund information, and your school records should include your withdrawal date.