GSTR 3B Taxable sales value wrongly

A user mistakenly filed their GSTR 3B with a significantly lower taxable sales value than intended for B2C sales. While the CGST and SGST amounts were correct, the taxable value was understated. The advice given is to rectify this error in the subsequent month's GSTR 3B by adding the difference to the taxable value. It's also recommended to ensure the GSTR 1 is filed correctly and to contact the GSTN or CBIC help desk for further clarification.