Airtel — direct payment from bank a/c through app not credited

I applied through airtel app rs.29 from my bank a/c for 150 mb data for 30 days. Txn id 920801 date 16 sept 2017 from mobile[protected]. Received sms "payment failed, contact your bank". I gave a written complaint to canara bank, srirangam. Bank confirmed payment. Debit raised in my passbook. I approached airtel at srirangam they couldn't help. Made complaint online. Received email from airtel customer support that they are concerned with payments bank, this is direct bank payment and to contact service provider. I do not know who and where to contact. I wish to know where my money has gone.