Need an advice on which lawsuit to file to HDFC branch, credit card branch and violation of confidential agreements

I had use a business credit card card which has the limit of 125000 lakhs but I never miss to pay the bill but after I damaged/loss my credit card there has been a lien amount as I ask for a new card but the bank told me to pay for the maximum debit amount. So I did an only than they sent me a new card but after a while I have seen a pattern in my statement that Late fee has been deducted every month. On the other hand a letter keeps coming and the statement also does not match. I realized that there has been an unjustifiable pattern So I closed my credit card because the collector keeps calling me more than ten times a day before the due Date. They even come to my house called my extended family telling them I took a loan and disrupted my work, my reputation. It is a year now since they told me I owe them 2lakhs and above even though I have close my card. They will not stop even though I have told them I have not received any new card.I have every evidence and sent it to them. But no progress has Been make. I even told them several times to sent me statements of the said credit card but they have nothing to show. The harassment is still going as well so, as my right and advice given to me by family as well as some lawyers What will be the most effective way to file a lawsuit including civil and criminal defamation, losing my business as well as my money . Can I file I lawsuit online which lawyer to approach etc