Credit Card overdue

I have got SBI bank credit card which they gave me after a lot of persuasion . I used the money from he card and was very much committed to pay the money i used but Bank never sent me statement for few month due to which i was not able to track my expenses made on that card . I approached bank and bank people and told them the same and the statement i received after chasing them was having almost 5000 fines on it which bank was asking me to pay . I made few partial payments after meeting one of the bank responsible credit card section incharge Mr Vineet who assured me that all the fines and charges will be dropped and you can pay the money in instalments . But later the same thing kept happening and bank keep putting fines and charges . I am ready to pay the principle amount which i spent in instalment s almost 40K but i am not at all willing to pay single penny for the overhead charges levied by the bank . Its and illegal approach and bullying the customer . Now they are sending me demand notices with criminal offence charges . please help me what should i do thanks,