Hello!
Repeated "unauthorised transaction" errors with AGL direct debit despite setup attempts and ample funds are a frustratingly common issue. This likely stems from internal AGL system errors, incorrect data entry on their end, or less commonly, bank-specific requirements. To resolve this, escalate within AGL customer service, formally complain if needed, contact your bank for their perspective, document all interactions, and seriously consider switching energy providers if the problem persists, as direct debit should simplify, not complicate, bill payments.