FBA returns 45 day period

Hi,

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How do I verify whether an FBA return has actually arrived at the fulfilment center within 45 days? I knew how to do it a few months ago and it saved me a couple grand but I am having a hard time to replicate it. The inventory ledger is only showing me that something has been returned but not which order it belongs to so I am having a hard time figuring out which orders have not been returned.