Enrollment could not be completed - stuck after failed mobile enrollment

I attempted to enroll in the Apple Developer Program through the Apple Developer app on my iPhone, but the process didn't complete. No payment was charged and no confirmation email was received.

Now I'm stuck:

- Website shows: "Your enrollment in the Apple Developer Program could not be completed at this time."

- Apple Developer app shows: "Enrollment through the Apple Developer app is not available for this Apple account, try in web."

I've already:

1. Waited over a week

2. Submitted a support case (Case ID: 102823448077) — no response after 5+ days

3. Tried calling Apple Developer Support — no answer

Has anyone experienced this? How did you resolve it? Is there another way to get Apple to reset my enrollment?