Distribution agreement to sell brands products on Amazon, how do we get this agreement to Amazon?

Hi,

We sell repair hardware for Upvc Windows and Doors on Amazon, most of the products we sell are OEM parts that have no barcode / packaging.

Historically we have purchased our own barcodes from GS1 which has allowed us to sell on Amazon without issue. Now Amazon are a lot more strict and from what I can gather will not allow us to do this anymore for protected brands, without a distribution agreement.

We have obtained a distribution agreement with a brand that explicitly states they are happy for us to sell their products on Amazon.

How do we actually get this distribution agreement to Amazon, so we can actually create and sell these parts on Amazon?

To expand on the issue I have twice opened a case to try and do this, however I suspect most responses are from Ai or someone copy + pasting off a script... as they seem to ignore my actual question and reply with some generic response.

I have gone along with these generic responses providing photos of one such product, however most don't have barcodes (from the brand) so apparently the "real world photos" are not good enough... this was why we were originally told we needed to obtain a brand agreement (which has taken months).

Now Amazon don't seem to want to acknowledge this brand agreement... can anyone advise how we can progress this?

Thank you.