Airtel — airtel refusing to refund for failed transaction

On 20th April I did a transaction ( txn#[protected] of Rs. 249 to recharge my airtel number, this transaction failed but the money was deducted from my account. After this failed transaction i did another recharge of Rs. 549 to sustain my service which was successful.
But when I gave airtel the details of my transaction telling them about the deduction from my account they said that the recharge was successful despite the fact that it wasn't and i had to recharge with another Rs 549. Initially they kept delaying the timeline for automated refund, from 5-7 days to 7-10 days.
In my email i got this transaction number