GSTR1 and GSTR3B f Y 2017-18

I have made B2B supplies of ₹5 lakh in Dec 2017 but mu consultant shows it as B2C in GSTR1 of Dec 2017 Later on he add This bill as B2B in month of March 2018 entering date of Dec 2017 but forget to delete the old B2C invoice now as per GSTR3B my turnover is ₹5Lakh for Dec 2017 which is correct but as per GSTR1 Turnover is ₹10 lakh how to deal with this??