Like other tech companies, Samsung occasionally deletes its stale accounts for security and to free some server resources. Such accounts which have been inactive for a long time are normally notified through an email that it would be deleted unless corrective action is taken. These are seriously concerning matters, including probably the rigorous deletion of your data, backups, and even cloud photos.

How to Save Your Samsung Account
If you want to save that old account, please simply log on to it by the time limit of deletion to inform the company that you are accessing and want to keep that account.
How to go About it:
Go to the website: https://account.samsung.com
Login with your ID (email or phone number)
Change the security settings if asked
Select Settings > Profile > Account Activity to see if you had recent activity
Just logging in once a year or six months for any Samsung service will hint that your account still matters to you.
What You May Lose If You Don't
Backups on the Cloud , Photos and videos in the Gallery, Notes and memos, Data on password manager, Purchase history and billing information, Associated services like SmartThings and Find My Mobile, Those data go out forever; you can not get that back even if you would reach out to Samsung's support.
Save Your Account From Getting Inactive in Future
To save yourself from going down this road again, do the following: Every 6-12 months, log on to your account, Make sure your recovery email and phone number are up to date, Add 2-step verification for extra protection. Once in a while, utilize any of Notes, Cloud, or Galaxy Store. This keeps your account active; thus, thinks it is "in use."

Just a Reminder
These accounts are the backbone of your phone ecosystem. Losing them can be a great pain when restoring backups, finding your phone, or using paid apps. So if you ever created an account at any point, especially during the time a Galaxy device was being set up, please log in today before the account shuts down by default.