NEGATIVE TAX LIABILITY

dear sir
i have more sales return than sales in November 2021

Sale - 100000 + 18000 tax
sales return - 500000 + 90000 tax

ITC - 0

so in this case how will i file gstr 1 and 3b

and tax difference of 72000 will get credited in my electronic credit ledger or what will happen to it.. how can i claim that amount?

please help