curl --request GET \
  --url https://api.withorb.com/v1/credit_blocks/{block_id}/invoices \
  --header 'Authorization: Bearer <token>'

{
  "block": {
    "id": "<string>",
    "balance": 123,
    "effective_date": "2023-11-07T05:31:56Z",
    "expiry_date": "2023-11-07T05:31:56Z",
    "per_unit_cost_basis": "<string>",
    "status": "active",
    "maximum_initial_balance": 123,
    "filters": [
      {
        "field": "price_id",
        "operator": "includes",
        "values": [
          "<string>"
        ]
      }
    ]
  },
  "invoices": [
    {
      "id": "<string>",
      "invoice_number": "<string>",
      "status": "issued",
      "customer": {
        "id": "<string>",
        "external_customer_id": "<string>"
      },
      "subscription": {
        "id": "<string>"
      }
    }
  ]
}