Gstr9 - annual return wrongly filed

Turnover for 17-18 is 58 lacs. All gstrs of relevant year filed succesfully . Liability to be paid at 12% was adjusted via purchase ITC and some cash payment. The Trouble. Instructions for GSTR9 mentioned that it is pre filled like other returns. I filed the system generated GSTR9. There was no liability or tax to be paid as per books and none was calculated by system. I realize that some colums of ITC belongs to what category were to filled . How do i rectigy my annual return of 17-18 online or manually at gst office.