Why can't you check the email address? I hope the email address isn't the iCloud Mail address for that same account. If it was, that was a big mistake. You're now in the position that any scammer would be in when trying to get access to an account. You are welcome to contact Apple and see if there is anything more they can do for you about the account. Refer to this page for Apple Support features ➔ Contact - Official Apple Support
Select from the presented options until you find a solution for your issue, or see if there is a chat or phone call contact method offered lower on the page (you sometimes have to narrow down the options multiple times before this is shown). If you do not see your issue, keep experimenting with any series of selections until you reach one that offers a chat session or a telephone call and get the representative to redirect you.
This support article has various country telephone numbers for contacting Apple for support and service ➔ Contact Apple for support and service - Apple Support
Apple has two related features, Activation Lock ( Activation Lock for iPhone and iPad - Apple Support ) and Find My ( iCloud+ - Find My - Apple ), which are designed to prevent anyone else from using an iPhone, iPad, or iPod touch if it's ever lost or stolen. Deactivation of either requires knowing the Apple ID and password that set the feature, or by placing a special request to Apple to reset the device. This Apple ID information essentially defines the current ownership of the device.
If you do not know the required information, are not the signed-in owner, or do not have Apple accepted proof of purchase, get the owner of the account to remove the lock or recycle the device. The device is otherwise useless to you.
Here are additional resources if you are the account owner, can find the previous device owner, or have an Apple accepted proof or purchase:
● Read this article for disabling Find My if Activation Lock has not yet engaged --> Turn off Find My on your devices and items - Apple Support , or this one to learn how to remove Activation Lock either on the device itself or on the web --> How to remove Activation Lock - Apple Support
● Reset device if you can prove to Apple's satisfaction you are the owner:
Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. This is done online* at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not provide many details in the article as to what is acceptable proof. Prior to this official service Apple typically required the original receipt** issued by Apple or an Apple Authorized Reseller. Note that while this will let you get use of the device again, it will not help you with lost access to an account.
* There is a special link for this service. To save time you should use it instead of https://getsupport.apple.com/
**Apple recommends you keep your receipt after you buy an Apple device. --> Keep your receipt after you buy an Apple device - Apple Support