External Product ID Changed By Amazon

Hey there,

We just went to replenish some of our inventory and noticed that Amazon had changed the External Product ID of one of our products.

They changed it from the accurate UPC that we own to another one of our UPCs on a product listing that has been closed for months.

Has anyone experienced this issue before? How best to resolve this effectively? I've messaged seller support, but I expect that to go on for days until it gets escalated to the right team.

Thanks in advance