Filed nill gstr4 return wrongly

Hi All,

I am in composition catagory of GST and I filed all the last four quarters return Nill wrongly.

And now I want to show the turnover for each quarter and pay the tax according.

Please let me know how can I do the amendment in all the returns and pay the tax.

And also what will the penalty for the same.

I have to show the turnover in ITR4 so need to do this on or befibe 31st July.

Thanks,

Anuj