Often in online payment system it happened it due to some server error or any other kind of technical issue is the payment may not be processed but deducted from your account in that case  contact the Biller such as many bills are provided by billdesk so that they may know where is the payment and also you can contact your bank but most likely bank will not be able to respond you quickly because the amount is debited from your bank so generally it takes two to three working days to reflect your amount in either side whether it will be refunded to your bank or it will go at the receiver and so nothing to bother about just its take some times and you should be handy with all the transaction data.