SBI Cards — credit card charges / finance charges reverse

I am using sbi credit card since 2 / 3 years but this time my card was upgraded from simply save to prime card and executive told me that my old card will work 60 days or till i will not use new card but my old card blocked from next day after talking abt upgradation and 23 was the due date but my card was blocked so i was not able to make payment of due amt as i was not aware about the fact that where i should make payment then i got new card on 26 th so i did all payment also rbi says there is three days grace period in credit card from due date if someone misses due date and there will not be any finance or late fee charges but sbi card is not following the norms of rbi they are not reversing me finance charges approximate 5871 rupees so kindly enlighten them about rules and tell them to reverse my charges