TATA STAR CREDIT CARD - INCORRECT CHARGES LEVIED

I am usging TATA STAR CREDIT CARD.They have not sent the statement on time and levied the financial charges on the same. I explained and clarified the fault that statement is not sen on time but still i paid the oustanding on receipt of the same. but they countinously levy the financial charges . Initially the amount was INR *** when this dispute started in July and now it reached to INR **** . Even i am looing my credit score. This is really frustating using such Cards. I raised the complaint also in consumer cell also tried to raise with RBI but their portal is not working. Pls help or guide me what shoul i do next.