Sir,
Rule 9 of Cenvat Credit Rules, 2004 stipulates that-
(1) The CENVAT credit shall be taken by the manufacturer or the provider of output service or input service distributor, as the case may be, on the basis of any of the following documents, namely :-
(a) an invoice issued by-
(i) a manufacturer for clearance of -
(I) inputs or capital goods from his factory or depot or from the premises of the consignment agent of the said manufacturer or from any other premises from where the goods are sold by or on behalf of the said manufacturer;
(II) inputs or capital goods as such;
(ii) an importer;
(iii) an importer from his depot or from the premises of the consignment agent of the said importer if the said depot or the premises, as the case may be, is registered in terms of the provisions of Central Excise Rules, 2002;]
(iv) a first stage dealer or a second stage dealer, as the case may be, in terms of the provisions of Central Excise Rules, 2002; or
(b) a supplementary invoice, issued by a manufacturer or importer of inputs or capital goods in terms of the provisions of Central Excise Rules, 2002 from his factory or depot or from the premises of the consignment agent of the said manufacturer or importer or from any other premises from where the goods are sold by, or on behalf of, the said manufacturer or importer, in case additional amount of excise duties or additional duty leviable under section 3 of the Customs Tariff Act, has been paid, except where the additional amount of duty became recoverable from the manufacturer or importer of inputs or capital goods on account of any non-levy or short-levy by reason of fraud, collusion or any wilful misstatement or suppression of facts or contravention of any provisions of the Excise Act, or of the Customs Act, 1962 (52 of 1962) or the rules made there under with intent to evade payment of duty.
Explanation.- For removal of doubts, it is clarified that supplementary invoice shall also include challan or any other similar document evidencing payment of additional amount of additional duty leviable under section 3 of the Customs Tariff Act; or
(bb) a supplementary invoice, bill or challan issued by a provider of output service, in terms of the provisions of Service Tax Rules, 1994 except where the additional amount of tax became recoverable from the provider of service on account of non-levy or non-payment or short-levy or short-payment by reason of fraud or collusion or wilful mis-statement or suppression of facts or contravention of any of the provisions of the Finance Act or of the rules made thereunder with the intent to evade payment of service tax.
(c) a bill of entry; or
(d) a certificate issued by an appraiser of customs in respect of goods imported through a Foreign Post Office; or
(e) a challan evidencing payment of service tax, by the service recipient as the person liable to pay service tax; or
(f) an invoice, a bill or challan issued by a provider of input service on or after the 10th day of, September, 2004; or
(fa) a Service Tax Certificate for Transportation of goods by Rail (herein after referred to as STTG Certificate) issued by the Indian Railways, along with the photocopies of the railway receipts mentioned in the STTG certificate; or
(g) an invoice, bill or challan issued by an input service distributor under rule 4A of the Service Tax Rules, 1994.
Provided that the credit of additional duty of customs levied under sub-section (5) of section 3 of the Customs Tariff Act, 1975 (51 of 1975) shall not be allowed if the invoice or the supplementary invoice, as the case may be, bears an indication to the effect that no credit of the said additional duty shall be admissible;
(2) No CENVAT credit under sub-rule (1) shall be taken unless all the particulars as prescribed under the Central Excise Rules, 2002 or the Service Tax Rules, 1994, as the case may be, are contained in the said document.
Credit note is not one of the documents prescribed under rule 9. Therefore it is safe to avoid taking credit on tha basis of credit note. Otherwise you have to waste you time and energy in unnecessary litigation.