Recent wallet credits (top-ups, welcome credit, manual grants), newest first.
ISO date-time when all of the account's numbers will be released for non-payment (the end of the 30-day grace period), or null when nothing is at risk. Non-null only for a pay-as-you-go account whose balance is negative; topping back to >= $0, or being subscription-covered, clears it.
Response of GET /api/v1/billing.