If you try to add it to your inventory and the device is in another organization's inventory you will receive a message informing you that the device has already been registered.
However, only those who sold it to you can remove it from the organization's inventory, Meraki support cannot help with this.
So my suggestion is to contact whoever sold it to you.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
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