Symbiosis Centre For Distance Learning — Malpractice during exam

I am a student of PGDSCM at SCDL. I have appeared for my semester exam but the mail has been sent from the university asking me to repay the exam fees and reappear for the exam due to malpractice during the exam. But the malpractice messaged popped up even before started the exam as laptop was on charging and they identified it as external device. I do not wish to reappear for the exam as they are doing it just for the sake of collecting exam fees. I want them to consider my examination valid as I am not guilty and have not malpractice during exam.