Hi ignacio111,
Thanks for coming to Apple Support Communities for help today.
It sounds like your iPhone Leather Wallet became paired with another device while it was disconnected from your Apple ID. In this case, the message would be expected. You'll need to find out what Apple ID it was paired with. This article can explain further: If an item or device is connected to another Apple ID
"Remove a Find My network item or device from an Apple ID
Use these steps to remove devices such as AirPods (3rd generation), AirPods Pro, AirPods Max, and iPhone Leather Wallet, Apple items such as AirTag, or Find My network items.
These steps also remove Find My Lock, which is the association of the device or item with an Apple ID. Find My Lock needs to be removed before you can associate the device or item with a different Apple ID.
- If the device or item is associated with the Apple ID of the previous owner, the previous owner needs to follow these steps to remove the device or item from their Apple ID.
- The device or item needs to be connected via Bluetooth to the iPhone, iPad, iPod touch, or Mac used to remove the device or item, and the device or item needs to be within Bluetooth range.
These steps are the only way to remove an item from an Apple ID and remove Find My Lock. They can be performed from any iPhone, iPad, or iPod touch, or Mac that's signed in with the same Apple ID. Apple can't remove Find My Lock for you."
Have a fantastic day!