Airtel — debit is not allowed even though there's money in the wallet

It's very disappointing when airtel promotes its wallet by "use instantly". I created an airtel wallet for irctc ticket booking. I credited wallet by 800 rupees but when i tried to buy the ticket, i got a message "debit is not allowed" neither the customer care reply to email ids.in our country getting tickets is not so easy. I feel helpless inspite of having money in wallet, i am not able to use it. My number is [protected]