So confused on this listing process, need some advice (NOOB ALERT)

Hey there, noob to Amazon to bear with me here.

So I own a small supplement brand and was hoping to get one of my products listed on amazon.

I bought a GTIN / UPC number / barcode from GS1 as instructed and went to list, then it says my GTIN isn’t valid, after chatting with support they say it’s because I didn’t put my brand name in the ‘brand name’ section. Okay, silly me. I go back and put my brand name, GTIN valid this time but then I am prompted with:

“You may not create new ASINs for the brand (insert my brand). If you believe the product you want to sell is not currently in the Amazon catalog and should be added as a new ASIN, please copy and paste the following URL in a separate window and complete the form: approval request”

I went and submitted everything and got a reply back saying I got declined, due to: “we identified that there is no verifiable information that (brand) offers HEALTH_PERSONAL_CARE on Amazon catalogue”

come to find out, there is another company on amazon with my exact brand name in a sportswear category, I assume this is why they are saying my brand isn’t in the health and wellness category?

they linked me here to submit proof this brand is mine: amazon/build-your-brand (can’t paste actual link here since it gets the post deleted but I clicked the exact one from the support ticket.

but the link is broken for me? says page not found?

Feels like a mess, I already reprinted my supplement bottles with the new UPC barcodes and I’m not sure if this means I literally need to rebrand? or who I reach out too or what I say?

Any advice from veteran sellers would be greatly appreciated.