Difference turnover furnished in GSTR 3B AND GSTR 1 FOR OUT WARD SUPPLY

Respected sir,. I had furnished difference turnover in GSTR 3B AND GSTR 1 FOR OUTWARD SUPPLIES IN PERIOD BETWEEN 01.07.2017 TO 30.6.3.2018. REGARDING THIS ISSUE I HAD RECEIVED SHOWCAUSE NOTICE FROM COMMERCIAL STATE TAX OFFICE. THEY ARE SAID YOU HAVE TO PAY TAX FOR DIFFERENCE TURNOVER AS PER SLAB RATE. IAM TELLING THAT WE WIIL RECTIFY THE DIFFERENCE TURNOVER IN COMING MEANS 03/2019 RETURN. ALSO SAID THAT WE WILL CORRECT DIFFERENCE TURNOVER IN ANNUAL RETURN OF GSTR 9. ACTUALLY WE HAD NOTIFICATION FOR THESE TYPE ISSUES ANY MISSED (PURCHASED) INVOICES OR SALES TURNOVER TO BE CORRECT UP TO 3/2019.IS IT CORRECT OR NOT.IF YES PLEASE NOTIFICATION NO AND WHAT IS THE SOLUTION FOR THE ABOVE QUERY