recover balance from blocked account

The support article If your Apple Account is locked, not active, or disabled - Apple Support has solutions for three frequently encountered reasons for an account to be disabled/locked/not-active.

If it is not one of the above three and Apple says it is permanently locked, Apple won't tell you why. Have a look at section VII-B of Legal - iCloud - Apple

You or somebody with access to your account may be doing something deemed to meet those criteria (yes, I know they are vague, but understandably Apple does not share its security system procedures).

As for lost funds, I do not know of any way to recover those. I personally do not keep a large balance in my account.

I'll also add that I have had my account for 21 years without issue. As I said, we do not know (except what is in the article) why Apple closes accounts. You may wish to review your account usage and see if there is anything they could have construed as abuse, etc. I must just have a well behaved account but I still play it safe as regards to balance. ;-)