our client is doing works contract business. we have filled the gst returns monthly. we are unaware that he get bill(supply of services) in the month of august 2017. we can not revise the gst returns. is it possible to show that bill in the month of march 2018 return and pay the gst tax accordningly?. if not what is the solution. my client is ready to pay interest for late payment of GST tax. will you please suggest me.