Can I amend Debit note(Purchase return) in next month's GSTR1 after receiving refund from supplier ?

I raised a EWB for Debit note/Purchase return of Rs.80K( 71429+8571(gst))

On receipt of goods supplier is now refunding me only 50% value of goods (50% GST too) on condition if I upload the whole value I mentioned in EWB(80K) and show rest 40K as loss in my account .

As per supplier I will have to pay ITC reversal of whole 80K and show 50% loss in my account books . But I think even if I upload the whole amount in GSTR1 and show 50% loss in account books ,I will have to pay half of gst which supplier have not refunded me in ITC reverse from my pocket,

Q1.Who is right in this ? Supplier or me?

Q2.Can I upload D/N of same value as in EWB (80K) ,receive my half payment and than amend the same DN in next month’s GSTR1 so that I don’t have to pay extra ITC from own pocket ?