Gstr-2 filing for claiming itc of missing invoices

my supplier has not uploaded certain invoices in his GSTR-1 return and i have claimed Input of the same in 3b because i have physical bills.

now the supplier is asking me to upload gstr-2 and those missing invoices and he will accept the same but gst website is not letting me save the invoice as it says the timeline for uploading invoice is not available.

I do not want to reverse the tax and the supplier is not uploading the invoices in his return, he wants me to do it.