There are many problems related to wrong recharge because of some mistake in the number entry or other issues. If it is Airtel postpaid and you have paid bill for wrong number, amount has been deducted and you want to recover wrong bill payment for Airtel postpaid, you need to confirm about the process from the Airtel customer care number. Register complaint for wrong Airtel bill payment through customer care executives.
You can write email to the Airtel customer care mail ID for postpaid users and use the mail to tell the problem along with reference number of wrong bill payment and try to convince for a wrong bill payment reversal.
Please let us know in comment about how much help you got from Airtel postpaid customer care and how did they respond. You cannot complaint for National Consumer forum for this however.