Credit

Dear Sirs, I have following questions. 1) Reversing sales of July2017. I have to reverse the sales invoice of July2017 on which I have paid GST in August 17 also filed GSR1 for July2017. Now my customer says that I have to cancel my Invoice as it is no more accetable by him.So we will have no receivable againt this invoice. How to treat this entry under GST please. I have to reverse the sales and reverse output GST also. Please advice. 2) I have to give lumpsum credit of Rs.2 lakhs to one of our customers. It is not Qty based. How to treat this under GST and how to show this entry in GST returns.Whether I will issue him credit note and reverse the output GST to that extend. Please advise. 3) I have made a GST payment of Rs.9810.00 on 3.9.2017 of reverse charge GST of July2017 with Interest of RS.50.00 for late payment.This amount is shown as a credit in our cash ledger on GST portal.Now how to utilise this credit of Rs.9810 and Interest of Rs.50.00 How I will show this GST returns.This Reverse charge GST was not shown in July2017 GSTR-3B not in GST1. Please advise how to adjust. Thanks n REgards Punjab Tayade email: [deleted]