Firstly, you should talk to your parents about this matter and discuss the steps with them that you can take. Secondly, you should file a complaint against those guys to your college’s principal and ask him/her to take strict action against them. Thirdly, If you will feel that the taken action is not sufficient then you can file an FIR against them. The person who is affected or witnessed the commission of a crime can inform the police by making a phone call to the police station or by going in person. Even a call made to the emergency helpline 100 can be treated as Information for the purpose of registering an FIR.