Gt Holidays Private Limited, Coimbatore - Extra money taken by GT Holidays Private Limited, Coimbatore for my air tickets to Singapore

I had paid INR**,*** (Receipt attached) on February **th to GT Holidays Private Limited, Coimbatore as an advance towards my travel with family to Singapore. The person coordinating for my travel was Ms. Sughasini. She was insisting on the advance to book my air tickets. I paid the money to the company on **th February. GT Travels did not hand over my tickets on the same day (February **th). The ticket was issued on *th March after constant follow-up with Sughasini. Infact she would come up with new excuses each time I asked for my tickets and with great difficulty Mr. Sajith from the same travel agency booked my tickets and send a word document with the tickets. The travel agent did not share any bill or invoice copy. When I went for applying visa, that organisation, had a checklist of documents which included ticket from the airline (they said that they could not process the visa with the ticket that the agent had issued – word document). Since it was a harrowing experience with GT Holidays we decided not to take the package from them and went ahead with another travel. After our travel from Singapore, I realized that the ticket cost for three passengers is only INR***** (mentioned in the ticket copy issued by Silk Air). I realized that the travel agent had taken INR**, *** in excess. When I contacted them for refund of the excess money, they are giving lame excuses. When I told them I was going to file a complaint against them in the consumer redressal forum, they have asked me to go ahead and do it and they say they cant do anything to sort out this problem. Please help me to sort out this issue. I also have copies of tickets that I am unable to attach here due to restrictions on the portal. Kindly do let me know if you would need the ticket copies and I would mail them to you.