Different companies and institutions have different customs and practices with respect to the timing of issuing a replacement check when requested when it appears that one has been lost. Your question does not pertain to a legal issue but rather a business practice with respect to your school where there is a 160 day wait until a new check is issued for a lost check.I would offer to pay for the fee to get a new check issued and the old one cancelled with the bank so that you can get your refund sooner rather than later.