Help listing a product

Hi there,

I’m new to selling on Amazon, I want to sell a unbranded product I have bought in bulk, the product has no GTIN on the item. So I have bought my own GTIN from GS1 and it won’t let me list as unbranded. Amazon told me I need to apply for GTIN exemption but it won’t let me it says it requires a GTIN.

I have sent a certificate from GS1 and a letter from the manufacturer stating I can sell this product on Amazon but Amazon are still adamant that I need to apply for a GTIN exemption. I am very confused and I have been trying to list the product for weeks now. Can anyone shed any light to what I am doing wrong?

The packaging is plain. No logo or brand writing so I can’t even register my own brand.