Getting calls from RBL recovery agency how to go about legally with it

i hade credit card from RBL and now i live with my parents. to whom i take care. i have 2.5 years baby but not married yet. during my birth i had to spend lot money to hospital bills and now i could not pay the bill. i work in company and these days my friends and relatives getting calls from the agency where they not only call them but also call their relatives and my team leader i have all the recording and i want to act legally against them they threat them and me. do not reveal there address and identity i have call recordings and i will arrange statements from the people who have suffered due to this please guide. how to del legally and to win the case because due to this i have been embraced my social prestige totally devastated and can i claim maan hani case . please guide in a way so that when i FILE a case i should have the knowledge of outcome and process