Input credit wrong claimed

As per the provision of GST act, you can claim the ITC upto the due date of return filing for the month of september 2020. i.e. Upto 20th october 2020.

So, claim the ITC of 3 lakh before filiing september month 3B.

Yes, As per the provision of GST act, you can claim the ITC of F.Y 2019-20 upto the due date of return filing for the month of september 2020. i.e. Upto 20th october 2020 or date of filing annual return, whichever is earlier.

So, You can claim the ITC of remaining 3 lakh which you forget to take in GSTR 3b return along with other ITC of that month up to the filiing of september month 3B.

Itc excess claim reverse on sales treated or any other options shown in columns number in gstr3b July,2020 return

ITC is relating to purchase So, you have to claim that ITC in 3B via table 4 Eligible ITC, column 4(A)5 all other ITC