Wrong service bills issued and return already filed

Service tax return can be revised within 90 days from the date of filling. 

If you have filed STR for Apr-Sep within due date you cant revised it. But STR For Oct-March you can make chnages and revised it. But keep in mind you can revise STR only once.

Thank You .

But is there any provision or procedure to correct the STR  for the period Apr-Sept

For Apr-Sep, the bills which are cancelled in that period, show it as Bills Cancelled/sales returns in the month of Oct. and claim input tax credit on such reversal of bills which are cancelled and carried forward such input till april 2017 from Oct end in the revision of such ST returns.