Export of services and FIRC - Service Tax

During the adjudication of SCN, with respec to to export of services, assesee submitted the forein inward remittance advice from the bank as proof of receipt of consideration in foreign currency. However department rejected the advice on following grounds - 1. These were just advice and not certificate (ie FIRC was not in a proper format) 2. inward remittance advice does not prescribed purpose of receipt Now when we contatced our bankers to isssue Foreign Inward Remittance Certificate (instead of advice), we are told that, banks has stopeed issuing FIRC ( for other than FDI) from 2016 and now only advices are issued. My question - In our view, no specific format of FIRC has been prescribed under services rules/finance act 1994. what is necessary is to proov receipt of foreign currency. Can department still challenge the export of services for not submitting FIRC in proper format ???