Invoices mistake

No time limit over as per section 39 (3) . return u/s 39 for the month of September (11 th October) following the end of the financial year which such details pertain

Madam thanks for your reply
then what is the solution to come out from this issue because turnover was offered in income tax and recipient of supply as claimed the input based on invoices

Sorry it's section 37(3) typing error

Sir one solution would be that you can pay the same by DRC-03 in option of voluantary payment alongwith attaching working of forgotten bill pertains to F.y.2018-19.

Then from our side it will be safe but from recipient side will he eligible for ITC which was claimed by earlier on the base of purchase invoice

Such ITC becomes ineligible subject to main condition of availment of ITC as supplier has paid GST what he has collected from customer.
We have one option In your case, you have collected GST from customer but didn't pay the same to Gov. whenever your customer received Notice from GST dep. as you have claimed more ITC in compare to GSTR-2A and then he has to pay the differential amt. At that time you have to reimburse such GST amt to Customer.I think this is the way to short out such issue..