Years ago, I returned an iPhone for a warranty replacement and no longer have the original device. I assumed returning it removed any connection to my Apple Account, but I recently noticed that the old iPhone still appears in my account's device list. The device now shows a phone number that does not belong to me. I have not contacted the number and do not plan to. There have been no unauthorized transactions or reports of strange messages from my contacts, but I am worried that the previous device might still provide access to my Apple Account. Could this be an account display error or recycled phone number, and what steps should I take to verify that my account and data are secure?
3 Answers
Before assuming the phone is being used to monitor you, look for concrete signs of account compromise: unfamiliar devices, changed trusted numbers, password-reset notices, purchases, or messages sent from your account. If none of those are present, a stale or incorrect record is much more likely. Removing the old device and checking your security settings should address the practical risk while also giving you a clearer answer.
The number shown under an old device does not necessarily mean that the current owner can access your Apple Account. Phone numbers can be reassigned, and older device records sometimes remain visible or display incorrect information after a replacement. Do not call or text the unknown number. Secure your account and ask Apple to clarify the device record through official support or an Apple Store if you want confirmation.
First, check the device list directly in your Apple Account settings and remove the old iPhone if it is still listed. Then change your Apple Account password, review the trusted devices and phone numbers, and confirm that two-factor authentication is enabled. If the old phone is no longer signed in to your account, someone who has it should not be able to access your current data. The displayed number may be stale account information, a recycled number, or a service-record mismatch rather than evidence that someone is using your account.
There have been no unauthorized purchases or reports of unusual messages. I will review the trusted devices and remove the old phone, then contact Apple Support if the information still appears.

That makes sense. I was mainly worried because the number looked unfamiliar, but I have not seen any suspicious activity. I will focus on checking the account rather than contacting the number.