Reverse Return of Goods that included Invoice #?

SOLVED

We received 20pcs on the first line of a multiple line PO (Items spread out monthly). One item failed testing prior to Receipt of Invoice 

The vendor Packing Slip contained an invoice #, so the shipping clerk used the Invoice # within the Return of Goods process

The vendor adjusted the invoice to 19pcs instead of issuing a credit memo. 

We cannot receive the updated invoice due to the following: 

Please advise remedy

Thanks in advance!