British Airways - Refund for unused ticket

On **-*-****, I had booked a ticket for a connecting flight of British Airways from Bombay to Montgomery via London with British Airways' agent yatra.com (https://www.yatra.com/) vide Booking reference *************. British Airways had cancelled the flight on **-*-****. So, yatra.com rescheduled my travel on **-*-**** on Flight No.BA**** vide Booking reference *UMO*Z. Accordingly, I reached Chhatrapati Shivaji Maharaj International Airport on time. I had valid travel documents including a US VISA. However, British Airlines staff did not allow me to board the flight on the ground that I was travelling on Student VISA. While booking the ticket, I had given the details of my Indian Passport. Based on the information furnished by me, my ticket was confirmed. Under these circumstances, if there was a policy of the UK Government not to allow a non-US citizen to travel in a connecting flight of British Airways, British Airways/Yatra.com ought not to have confirmed my ticket. The fact that my ticket was confirmed by British Airlines/Yatra.com clearly shows that I was entitled to board on Flight No.BA**** on **-*-****. However, I was not allowed to board the flight. Due to this, I could not reach my destination on time. British Airlines staff at the Airport was non-cooperative. The cancellation of the initial flight on **-*-**** and the subsequent act of British Airlines staff not allowing me to board Flight No.BA**** on **-*-**** not only caused me a great financial loss but also mental harassment. I also delayed my journey. I was required to book a ticket on United Airlines Flight No.UA-*** on **.*.**** vide booking reference No.MEYMOB by spending extra money. On enquiry, the customer care representative of Yatra.com told me that I am not entitled to get a full refund of my ticket and Rs.*Rs.*****/- will be deducted towards the cancellation charges as per the policy of British Airways. The cancellation of my ticket was not due to my fault, but because of the negligence and carelessness of British Airways in confirming my ticket against the so-called policy of the UK Government. Deducting cancellation charges for no fault of mine would amount to add salt to my injury. So, I am entitled to a full refund of Rs.**,***/- without making any deduction towards the cancellation charges of my ticket (Booking reference *UMO*Z). Till date, I haven't received any refund from Yatra.com/British Airways.