Control Accounts (Practice & Revision Kit)

Hello John

1) Could you please explain this sentence? and why does it not included in the payable ledger control account?
A supplier’s account in the payable ledger, with a debit balance of $800, has been included on the list of payables as a credit balance.

2) Can you list things which to be included in control accounts and which to be included in the list of balances, or where I can clarify about it?

Thank you