IDFC Bank — bank is not providing refund on unsuccessful transaction

Address:

560076

I have booked 4 flights on 17th june'17 with yatra.com by idfc debit card and amount is 3211rs. Out of four, only one transaction was successful. It means i'm supposed to get three refunds but i got for two. I have informed the same to bank in last week of june, they asked me to wait with stating you'll get your amount.
So one transaction is disputed and i have raised one dispute form also with bank on 16th july'17. But they're not providing any solution. I have checked with yatra.com, they're saying they've returned the amount and they gave full details with arn no. Which i have shared with idfc bank in july itself.
Bank is not returning the money and now they're saying it'll take time upto 11th sep'17. How is this possible bank is not able to fetch where the amount exactly is..? They're playing with customers. And there are so many customers who are facing same problem with this bank.
Can you please take action on immediate basis..?