463 Points
Joined September 2019
Please go through the notice. Official have given you their working and differences in this notice DRC-01A and along with 73 CGST Act. Demand the amount.
Do all your working whether the difference in your GSTR-1 or GSTR-3B. If you agreed the difference. Then login portal and find your notice. Submit reply against this notice and make payment.
Please contact your Tax Accountant or Chartered accountant to fix this issue.