Why did my account be disabled
Why is my account disabled and how do I get it undisabled
iPhone 11, iOS 15
While no one in this user-to-user forum can answer a “Why” question, the general answer is that you owe Apple money for some reason, so they disabled the account to get your attention so the issue can be resolved.
What was the result when you followed the guidance in the Related Article above your name on this page, that you were reading just before you posted here? Specifically, there is a link in the article to contact an Apple representative to discuss the issue.
This is not a problem you can solve on your own; you must contact Apple.