If its the same number block it. Dont call it back, it only confirms you called back so you give them the authority to call you. There may be other issues like charges for the call and confirmation that you want the call. but if you do receive the call first thing is ask the name of the company and make sure you get the correct name. I doubt they will but persist beyond this point but even repeat it 2 or 3 times.
If they don't hang up on you by now just waste their time, make sure you tell them you are recording this call. Call frequency and time is the 2 most precious things to them. They are only the dialers there may transfer you to the qualifiers if they did this then you fooled them and are really wasting their time. Dont give any correct information, but lead them on.
You can tell them that the FBI raided and closed down many call centers in India they also arrested Amit Chauhan. If by any chance you managed to get anywhere, then at your pleasure, tell them you did not solicit a call from them, you have the correct company name and phone number and if there is another call you are going to turn this over to the authorities.
https://www.bbc.com/news/technology-51740214It will cut down on calls eventually it takes time to take your number off the automatic dialers. Oh I forgot one thing, if you are pretty sure they are from India then ask them where on the train did you climb on to?