Debtors became bad debt

Hi,

During YE 31.3.11,a company ,had raised a service invoice and payment was outstanding to be received as on 31.3.11, during the year 2011-12, the amount is not receoverable from the debtors and so Bad debt, in such circumstances, what abt the Service Tax element, whether the same shall be reversed or should form part of Bad debt

The bad debt is accounted on 31.3.12 

In respect of Service tax,with amendment in POT,accrual basis is adopted  and all the payments were done accordingly.