Product selling as multiple items but EAN is for single item

I have an EAN 6001038272555 for a single item, but when I try to add a single product, Amazon won’t let me as ASIN B01GGNX0NS is already using the EAN - Robertsons Salt and Vinegar Spice 100ml - 2 pack

I have a few issues with the barcode on single products being used to sell multiples. How can I get around this and use the barcodes for the single products they are intended for?