Icici personal loan

I had taken a personal loan from ICICI Bank in the year 2007.....which I was unable to unsay due to an unstable financial situation. I started getting calls from the recovery agency from end of August 2017 onwards. The first call I got was from a person named Ramesh Chatterjee who claimed to be a lawyer and calling on behalf of ICICI bank to initiate legal proceedings and issue NBW against me. He said that he was calling from Tees Hazari court, so when I asked him his chamber number or office address, he refused to give any details and that's when the abusive language and threatening started. This was not on the first call. I am also being contacted by another person named Chotey Laal. I have been contacted by other people as well for the same loan, however I am mentioning only these 2 names because they are the ones who have been constantly calling and threatening me and using abusive language. However, today I got a call from a lady for the same issue and when I tried to explain to her that I have already explained to Ramesh Chatterjee & Chotey Laal that I can only repay back this loan in installments, she started abusing, when I immediately disconnected the call. However, what I am really shocked at is that today only they even called my cousin brother and used abusive language with him. How on earth could they have obtained my cousin's number ? I have already informed the agency that they may proceed legally against the recovery of loan in case they are not willing to accept installments, but the trauma continues. Uptil now it was fine, but now that they are getting to my family and that too without my permission, is not at all acceptable and therefore I would like to know what my options are. I don't want to file a complaint with the bank as they never take any action and just keep passing the buck. Besides this is a very serious issue and cannot be accepted. Would really appreciate some good advice.