My other Apple account is locked

I am from China and now live in the US. I have a US Apple account specifically for purchasing and downloading apps from the App Store (because the Chinese App Store doesn't offer some apps I need). It's not logged into on my Apple devices, but I can access its associated email and phone number.

A few days ago, I tried to log into this account on my Mac App Store, but it prompted that I couldn't log in (I may have misremembered the password). I tried to reset the password, and it showed "account locked". I used the associated phone number to request access, and the feedback I received was likely "under review, Apple Support cannot expedite this process" – I don't remember the exact wording.

Now I have tried various methods provided by Apple Support to reset the password or request access, but it consistently shows "This Apple Account is locked and can't be used".

Please advise me on what I should do. Thank you!