Punjab National Bank [PNB] — deduction of amount 697.38 without any explanation

Address:

Haridwar, Uttarakhand, 249404

On september 18th, 2017, i received a text stating my account had been debited with rs. 697.38 on[protected], 11:28:45 and i did not receive any text prior to that or after that explaining why the amount was deducted. The same day i visited the pnb branch (Located at singhdwar, haridwar, uttarakhand) where i had opened my account under the student scheme and there i wasn't given any reason as they said they had contacted their seniors regarding this problem as every student from university, gurukul kangri university, who had opened an account in pnb was facing this same problem, and it would take about a week to hear back from them.
We were told that it's possible that we were charged with this amount for paying our college fee online through our pnb account but at the time of payment there was no mention of any kind of extra charge, besides we've already talked to they gateway provider of the fee transaction, hdfc bank, and they've confirmed that they provided the gateway free of charge as a part of their agreement with our university.
Kindly look into this matter.