HDFC Bank Credit Card — fake charges

Address:

Pune, Maharashtra

my name is nagneth madhavrao kendre Bill dated 07/02/2015, Bill of January with amount 19500, I paid late bill 3 days late hdfc chanrged me 4523 finance chanrges ...i called customer care and asked what are those chanrges he told me ...its late amount interest ...i asked what is interest he told 3% for 1 month. According to mathematical calculation for 19500 amount 3% is 585...from HDFC calculater 3% for inr 19500 is inr 4523. My cell number is [protected]..please help me on this.