One list of what you were charged, what it bought, and how it was funded.
Ledger entries are immutable and recorded in exact integer units. A correction appears as a new entry, not as an edit to an old one.
A failed availability check. Nothing was charged and no purchase existed, so there is nothing to list. If you expected a purchase and find none, check whether you saw Provider unavailable. — that is the same event from the other side.
A purchase can be part internal balance, part USDC. That shows as one purchase with both funding sources, and gas or transaction surcharges attached only to the USDC portion.
If a purchase looks settled but the capability never arrived, that is the case Refunds and failed delivery covers. Note the purchase and the agent before raising it — those two facts identify it unambiguously.
An agent can read its own wallet balance and checkout status. It does not get your billing history — that is yours.