Fix Amazon Variation Listings

My size- and color-based products are already set up in a parent-child structure, yet the variations refuse to surface on the live detail pages. I need someone who knows Amazon Seller Central inside-out to diagnose where the link is breaking, rebuild or upload the correct flat file if necessary, and get every variation showing exactly as intended.

Key points to tackle:
• Restore proper visibility for all size and color variations under each parent ASIN.
• Ensure titles, SKUs, and attributes remain intact so nothing loses ranking or indexing.
• Provide a short summary of what you changed so I can replicate the fix on future listings.

I’ll grant you temporary Seller Central access (or you can work from the bulk file if you prefer). Once every variant is selectable and displaying stock/price correctly, we’re done.