29 May 2012
Relevant provisions in respect of your query are given under rule 6(3) of Service Tax Rules, 1994 as under:
(3) Where an assessee has issued an invoice, or received any payment, against a service to be provided which is not so provided by him either wholly or partially for any reason or where the amount of invoice is renegotiated due to deficient provision of service, or any terms contained in a contract, the assessee may take the credit of such excess service tax paid by him, if the assessee.- (a) has refunded the payment or part thereof, so received for the service provided to the person from whom it was received; or (b) has issued a credit note for the value of the service not so provided to the person to whom such an invoice had been issued.
Thus on the basis of above provision it is concluded that if due to above reasons amount is debited by your vendor then you can cliam the cenvat credit but you are required either to refund the amount or issue credit note in respect of same.