New Private Label Seller – Stuck at 0% Buy Box, Ads Not Delivering, Inventory Partially Received – Advice?

Hi everyone,

I’m a new private label seller and recently launched my first FBA product (ASIN: B0FBGTSSGG) on Amazon UK.

So far,

I’ve: Sent in 78 units to FBA, but only 68 are marked as “Available” — My product is Prime-eligible, no other sellers, and I'm using Amazon Sponsored Products ads, Ads say “delivering” but have shown no impressions, clicks, or spend in 5+ days, Buy Box win rate is 0%, and I have no featured offer visibility.

I’m aware that Buy Box is needed for ads to show properly, but I’m wondering: Could the incomplete FBA receiving be blocking full Buy Box eligibility?

Is there anything else I might be missing that could help unlock the Buy Box or trigger ad delivery? I've opened a support case, but would really appreciate advice from anyone who's been through this as a new PL seller. Thanks in advance!