Need help to find out how I lost all my music

If you are trying to say that you are an Apple Music subscriber and your card was declined when your subscription renewed last, then yes, that's why you lost it. You do not own that music, you were effectively renting it. As long as you keep paying, you can keep listening. When you stop paying, you lose access to it.

That's how subscriptions work.

Since you've provided no information, we can't begin to guess.