Air India — Not refunding the cancelled ticket amount of 4995

Website:

www.airindia.in

I booked 2 tickets of ₹4995 each on 4th September of flight of air india from
New Delhi to Bangalore for 4th nov.
And I cancelled that ticket on 5th September due to some reasons.
It was written that the full amount will be refunded back that is ₹9990
But the next day they refunded only ₹4995 that is the among of only one ticket.
After that I called them many a times saying that I have not received the full amount but they said that it's showing complete on their side.
Then I also mailed them the screenshot of the amount I received of my passbook from SBI app.
But still no reply from their side

Please help in resolving the issue.
Thank you