Reimbursements?

Hi, I currently have two item msissing from my inventory, both of which I have received reimbursement for.

The first was and Item I sold for £39.99, but the order was cancelled as Amazon damaged it before shipping. My take after fees would have been £29.77. Amazon have closed the case with a reimbursement of £16, and no sign of the inventory.

The second was being listed for £79.99, which was the lowest asking price, meaning I could have valued it higher and my price was on the low end. When my FBA shipment reached their centre, I saw 1 next to FC processing so I can only imagine they received it but then forwarded it on to another centre? The stock wentissing and so I received compensation... For £15. I wasn't too worried as my inventory now showed 1 in stock, so I figured they had managed to replace it with their own supply. But now today it shows as 0 stock.

My question is, what can I do? As with many resellers, the only invoices I can show is for the low price I paid for them, which doesn't reflect their true value. Especially since they actually cost me a completed sale on the first one.

If I sent them invoices showing I only paid £5-10 for each of these, is that all I can claim from Amazon? Or can I claim the value they lost me on a potential sale?