Credit card misuse and misbehavior by recovery agents

I had American Express credit card whose phone and email details were changed by some frauds by fooling me and . When I saw my online transactions I saw some unauthorized transactions. I immediately called American Express customer service and got my credit card blocked and told them that there was a fraud people who were misusing my credentials and do not issue a new card. This was in 2017. I then paid all the outstanding of the card. I did not hear anything from them after that. In 2018, when I was checking my credit score, I was surprised to see a second Amex credit card had been issued and around 1.4 lakhs were used from the credit card. I never got any notification because the registered mobile number and email ID were changed. I approached Janakpuri police and lodged a complaint against the agency. After multiple attempts a joint FIR was filed along with 2 other people who were duped by the agency. This was in April-May 2018. Then I started getting calls from recovery agents of American Express threatening FIR for cheating, so I visiting American Express Gurgaon office and explained the scenario. I told I dont want harassment at workplace or at home and lets settle this amicably if there was a small settlement amount as I was not sure how much time the police process will take. But American Express reduced 10% and asked me to pay the balance. I refused and sent a complaint to the American Express grievance cell. The matter is still not solved, the police has not made any progress so the stolen money is not recovered. Meanwhile, the american express recovery agents are getting restless, calling me multiple times during office hours and accusing me of being a thief, now they are even calling after 6 PM violating the RBI guidelines. What are my options in this case, the amount is very big and I think the American Express people also to be blamed to issue a card without proper verification and inspite of me telling not to issue a new card.