I can't look for another ISP this is the only one available in my area though, I talked to the BSNL guy again, now he wants the exact URL for the gaming servers so that he can ping and trace route where the exact problem is. He said it is probably routing issue only. I have mailed the developers of the game to know the exact server addresses they use. I am on PS4 so there is no way to check it like we do it on PC using resource monitor. But the same game is cross platform so if they don't provide me with a satisfactory answer then I will have to install it in my PC and just to get the server address using task manager.No Problem, Just don't get your hopes high. It will be fixed when they wish to do so.
At-last, I would look for alternative ISP.