Apple Account email inaccessible due to deceased ISP: How to regain access?

You may need access to the email address if what you are doing requires being able to read messages from Apple telling you what to do next. My email provider "died" last year, but they gave us 6 months notice. Since Apple Accounts now form as much as part of your equipment as display does, you need to be proactive about that sort of thing.

You will have to contact official Apple Support and hope that you have sufficient other ways to prove to them that you are the account owner.

You also do not say how exactly you wish to "reset" the iPhone. They can be locked in several different ways, each with a different solution which may or may not require access to your email. You tend to only need to have access to email if Apple is trying to rescue an account for you, not for resetting a device. If part of your resetting means you do not have the account information then the problem is not the resetting process, it is an account issue.

1) iCloud: Activation Lock - Activation Lock for iPhone and iPad - Apple Support - This is a security feature so only legitimate (e.g., not stolen) use of devices is possible. Read this support article about how to remove Activation Lock --> How to remove Activation Lock - Apple Support - If an activation lock was put on a device, only the owner of the account that applied the lock can remove it. Get them to remove it or return the item for a refund. If you are the owner and have the original Apple receipt to prove that, see the part at the end about asking Apple to reset the device.

2) Device lock: If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled, read this support article if you are using iOS or iPadOS 15.2 or higher --> If you forgot your iPhone passcode or your iPhone is disabled - Apple Support or here if you do not meet the criteria for the previous method--> If you forgot your iPhone passcode or your iPhone is disabled - Apple Support

3) Carrier lock: Read this article about how to unlock your iPhone for use with a different carrier. --> How to unlock your iPhone for use with a different carrier - Apple Support Only some carriers offer the ability to unlock iPhone for use on any carrier. Follow the instructions in this article to unlock your iPhone.

You don't need access to the email account used for the Apple Account. You will need to explain more what the problem with the Apple Account is. It could be Locked, Disabled, Not Active, or the password may need to be reset. That does not require access to the email account either.

It is not clear what you mean by resetting a phone seems to need it. If the person reset a phone and sees a screen that says Locked to Owner and are required to enter the Apple Account/Password, it may have been set up by someone else and they will not be able to proceed. Again, nothing to do with the ISP of the email provider and there is no check on whether there is access to the email account or if they are receiving emails.

Thank you, these look like they might bear fruit!