Service tax returns compliance requires timely filing; penalties apply and limited revised and annual return provisions exist. Every person liable for service tax must furnish a half yearly return in Form ST-3, file electronically at the prescribed portal, and where provisional assessment applies submit monthly reconciliation in Form ST-3A. A registrant must file a nil return if no taxable services are provided. Single registration for multiple services or locations permits one ST-3 with separate details. Penalties for late or non filing are prescribed under Section 70 and rule 7C, rule 7B permits limited-time revised returns, and rule 7(3A) requires an annual return with specified filing and revision rules.