Reliance Petroleum — Extra charges regarding

I have used ICICI Debit card for my car fuel on 02 of may 2017 in reliance fuel station of rupees 750 but on 09th of may 2017 you changed me rupees 21.55 regrading usage of debit card on 2nd may 2017 i ask ICICI BANK they told you only charged is not fair thing your are doing on the time of card usage you charged 750 only after few day y are u charging 21.55 extra kindly refund my 21.55 rupees asap thanks