Getting error message in filing gstr1

i wrongly entered some july month invoices in august month gstr1. then wiyhout removing the invoices i filed the july month gstr1 with that invoices. thereafter i tried to file gstr1 of august month that time the july month invoices entered in august month gstr1 was automatically removed. then i entered the correct invoices in august month and try to submit return but getting error message ' errror in submission' - the invoice no.....(july month invoices) already filed in 072017. but the that invoices not showing in august month form to correct/remove. what will i do any advice