Kotak Mahindra Bank — why are the tbms charges cutting down from my account?

When my account is 811 with maintaining policy of zero balance per month my bank is continually charging tbms charges without prior notice and i don’t know why they cut down these charges from my a/c. I got cut this amount two times of this month within 10 days. First, tell me the reason of these charges and second if the charges are not applicable on my account then make a refund in my a/c.