Anna University — opto.. re exam.. cancellation request

Opto electronic devices examination was held on nov 2nd 2018 for ece department. However based on the feedback received from principal of some affiliated colleges, it has been informed that re exam will be conducted. I would like to know as to why the students should pay for it. We don't want to go through the mental stress of taking up the same examination again. Already we're affected by the poor rescheduling of examination dates due to the gaja cyclone. Please do consider and understand the mental agony and pain the students have to go through in the process of taking the reexamination