Hi wn-14,
welcome to the Apple (user-to-user) Community!
Re: TFA device is lost. Can’t retrieve data. My mum’s phone is gone.
Commiserations on the lost phone ... your mum is fortunate to have your help!
Am no expert in this area, yet your questions deserve some response.
Fortunately Apple Support has articles online (links below) that may be helpful.
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Re: "We want to login to icloud.com to retrieve data before 30 days are up.
Is it possible to set another device logged in to the same Apple ID to receive TFA codes? "
If your Mum has any other device (eg: iPad or computer) linked to her Apple ID, it is possible to have a code generated on that, in order to log in:
More info: Get a verification code and sign in with two-factor authentication - Apple Support
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Re: "Is there any other way to go about this?"
It seems your phone number would need to have been listed as one of her trusted numbers before phone was lost.
If all else fails, at the bottom of the article above is info. about using "Account recovery" with proof of identity.
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More info: See the Apple Support article Two-factor authentication for Apple ID."
Eg: says:
What is a trusted device?
"A trusted device is an iPhone, iPad, Apple Watch, Apple Vision Pro, or Mac that you’ve already signed in to using two-factor authentication. It’s a device that we know is yours and that can be used to verify your identity by displaying a verification code from Apple when you sign in on a different device or browser."
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Apple Support also has other articles online to help those who find themselves in the situation of phone is lost:
See: Find your lost iPhone or iPad - Apple Support for any tips that may help
Sign in and use iCloud.com - Apple Support
says:
"If you lost your trusted device, you can still use Find Devices by clicking the Find Devices button".
See Sign in to Find Devices on iCloud.com.
Eg: that says:
"If you’re asked to enter a code from a trusted device
- If you go to icloud.com
- and sign in with your Apple ID, you may be asked to enter a code sent to a trusted device.
- To continue without entering a code, click the Find Devices button at the bottom of the window.
All the best :-)