[Resolved]  Standard Chartered Bank — Statement shows excess amount(credit) but they are leaving late charges and Interest

Address:

Bangalore, Karnataka

I am using standard chartered credit card from long time, i am an add on card holder, my wife is primary card holder, Initially i used to get 2 different statements for each card(add on & primary card) but on Feb2013 statement i received statement which shows (at header level) both the cards mentioned on this statement and says "Total Outstanding amount : 357.50CR" (i was having 372.81 outstanding balance in add on card and 730.31CR in primary card ) they showed total outstanding as : 357.50CR , as total o/s shows as credit, i thought now both the cards statements are combined and they adjusted towards each other and showed credit but now when i checked, they have charged me 100+ ST towards late charges and again they will charge me interest charges.
Please help me as these standard chartered bank is cheating customers very badly.
My question is:
1. If i need to make both payments seperately, then why i got both the card details in one statement?
2. and why the statement is showing as credit amount (excess) in my total outstanding balance section.