Admissibility of prior year service tax refund rejected

Hi all

I need expert advice on the following issues -  Service tax refund (CENVAT credit) pertaining to FY 2008-09 of a Assessee (Service Export Company)  rejected in 2011-12. In 2008-09 assessee shown under "receivable" in finacials. In 2011-12 service tax department rejected claim. Now, my question is , if i want to write off this receivable, i mean charge off to profit and loss account, whether the same is admissible item in compuation of business income?

Need to solve this. Anyone can help me with case laws, rules and regualtion.

Thanks