Itc on return goods

Dear Sir/Madam,

Ours is a pharma organisation.  We have received sales return from some of our dealers.Now my doubt is where I can see their GST Payment for the same,  whether is it available in GSTR2A or some other menu to avail ITC.  If they have not made GST payment how to pass credit note whether on the total amount or part amount. For instance 10,000/- worth goods returned by a dealer(9000+1000 GST) shall I pass Credit Note on 9,000/- or 10,000/- Further if there is any expiry stock (say 500/-) how to pass credit note.  Please clarify

Thanks in advance

Regards,

M.Gururaj