Safe T Claim help

I filed a SAFET claim, and Amazon keeps denying it because they don’t reimburse “lost” packages, but the package was delivered. The tracking number says so, and UPS confirmed that it was delivered and signed for. What am I supposed to do now? I am not an FBA seller.

I paid for shipping through Amazon and got a refund of $4.49 for the shipping, but not for the $48.50 cost of my product. Because the customer never returned the item, I lost inventory and this refund was deducted from my sales. It makes me want to give up on selling anything on Amazon altogether. I have no control over returns or the process.