First, contact a good and sincere advocate and he will study the facts and issue a comprehensive legal notice to the opposite party. Keep that notice as a bonafide document of facts adhere to that notice and file complaint in Consumer forum as a party in person. The cost of the legal notice may be less than Rs.500/- and that notice saves you from other expenses and entire expenses through forum may not exceed Rs.500/- in all. Every forum was provided with help desk to assist consumers.
Instead of proceeding party-in-person it is advisable to consult a local prudent lawyer with relevant facts/documents for appreciation, guidance and proceeding, if you are seeking some positive result against the opposite party to protect your interest.