Regarding Credit Card OutStanding

I was having HDFC Bank credit card, a Few Months Back I made one transaction after confirming on bank call center that whether my transaction can be converted into EMI, they said yes it can be, but after swapping the have denied converting my transaction in EMI and they have raised the outstanding bill of total amount. Due to the big outstanding amount I have failed to pay the same. I have kept asking to convert the amount in EMI but they didn't. Somehow I managed to pay the Minimum balance but it was raising my Interest amount and no robust solution was provided by the bank. after few, they have blocked my salary account and recover 60k from there without any intimation, now My difference balance left to around 40K, due to that all my EMI has got bounced, and my total credit rating was ruined. Now again they are asking 1lacs rs as the outstanding amount I have and now they are ready to convert my outstanding to 5 EMI. Now my concern is when it possible to convert my outstanding into EMI now why it has not been done that time, Now they are harassing me like anything to pay the whole amount where I have paid almost all my outstanding. what could be the solution for the same.