Immediately file a criminal complaint against them for cheating by impersonation and they will be arrest for their illegal acts/offence.
The FIR will be registered under section 416/419/420/ 34 of IPC
416. Cheating by personation.—
A person is said to “cheat by personation” if he cheats by pretending to be some other person, or by knowingly substituting one person for another, or representing that he or any other person is a person other than he or such other person really is.
Explanation.—The offence is committed whether the individual personated is a real or imaginary person.
P
Section 419 Punishment for cheating by personation.—
Whoever cheats by personation shall be punished with imprisonment of either description for a term which may extend to three years, or with fine, or with both.
Section 420
Cheating and dishonestly inducing delivery of property.—
Whoever cheats and thereby dishonestly induces the person deceived to deliver any property to any person, or to make, alter or destroy the whole or any part of a valuable security, or anything which is signed or sealed, and which is capable of being converted into a valuable security, shall be punished with imprisonment of either description for a term which may extend to seven years, and shall also be liable to fine.