Rectification in form 16

I have left job in September 2018 but my employer issued form 16 having been included whole salary in single figure from April 2018 to Sep 2018 in March 2019 itself as they had not shown my salaries in previous quarters. Just to avoid revising past three quarters return they include my salary in March while i have left job in September 2018 itself. I requested them to rectify this mistake as this can be conflicted with my other income. but they are refusing by saying u can complaint wherever you want this would not be rectified. is it ok to show resigned staff's salary after 6 months of resignation. please give me remedies to rectify this mistake.