Difference tax liability between GSTR 1 & GSTR 3B - Goods and Services Tax - GST

A taxpayer has wrongly filed his GSTR 1 with excess liability...and the same has been rectified in GSTR 9 along with GSTR 9C ..disbursed the actual liability as per books of accounts...bt department claim the liability as per GSTR 1 which was wrongly filed...now what is the proper solution??