Disable Activation Lock status and remove Find My

Hello,

I bought used equipment from Ebay. When setting up a new user and signing in to iCloud. I see Find My appear with email address of the previous owner. This makes me concerned about my data being lost.

I tried to contact the seller to remove Find My from the account but they say the device is offline.

Please help me how to disable Find My and remove the previous owner's email address from the device.

Best regards,

Quang