Any Possible Solution to FBM Featured Offer Eligible “NO”?

I used to handle the fulfillment of a highly successful product myself, with assistance from a family member who owns a warehouse and fulfillment center in Edison, NJ. The product was selling well, ranging from 50 to over 250 orders per day. I would purchase labels and provide them to my relative, who managed the shipping and preparation process. Unfortunately, there was a lapse when he forgot to deliver over 20 orders due to a file download error during his drive.

I typically checked only a small sample of orders, around 1-10 out of the 200, to confirm their shipment status. After about 10 days, I began receiving refund claims from buyers, and A to Z claims started to accumulate. Consequently, I lost eligibility for the BUY BOX on any FBM products, even with competitive pricing. As a result, the product, which used to sell over 250 orders per day, now struggles to reach 10 orders. I’m seeking guidance on how to resolve this issue. If anyone has experienced a similar situation, your advice would be greatly appreciated.