Goibibo India Private Limited - Refund from Goinibo

My flight from Delhi to Ludhiana ( AI **** and PNR-YWM**) was involuntary cancelled by the airlines (Air India) on *rd of May.
Flight was booked through Goibibo which is insisting me to get the endorsement copy from the Airlines office so that they can confirm whether the flight was even cancelled or not. I have been to regiona offices of Air India and also spoken to Airlines many a times and they confirm that the flight was cancelled but regional offices /customer support centres are not entitled to share such endoraement copies. Goinibo is adamant for such copy and my money is stuck witj Goinibo.
Thanks