We had entered into Registered Building Lease agreement during April, 2003 for a lock in period of 5 year. At the time "Service Tax" was not introduced and as such no specific clause of service tax was mentioned at the agreement. On introduction of service tax the service receiver (tenant) was immdiately intimated for is obligation towards service tax. on enforcement of the tax, the rental bills were promptly sent to service receiver for collection rent and service tax giving service tax registration number. The tenant has not paid the service tax till date. He however has been paying the rentals and other charges promptly stating that, no such contractual obligation exists as per the lease nor the law mandates to pay service tax. Tenant has since vacated the premises on completion of lock in period. We how ever have been paying the service tax on the rentals received and with held the service tax amount from the deposit held. Please clarify the position and advise for recovery procedure.