curl --request GET \
  --url https://api.voltview.co.uk/v1/sites/invoices \
  --header 'x-api-key: <api-key>'

[
  {
    "isStatement": true,
    "supplierName": "<string>",
    "supplierAccountNumber": "<string>",
    "customerName": "<string>",
    "billingAddress": "<string>",
    "items": [
      {
        "invoiceNumber": "<string>",
        "invoiceDate": "2023-12-25",
        "dueDate": "2023-12-25",
        "chargeStartDate": "2023-12-25",
        "chargeEndDate": "2023-12-25",
        "netAmount": 123,
        "vatAmount": 123,
        "totalAmount": 123,
        "previousBalance": 123,
        "outstandingBalance": 123,
        "supplyPoints": [
          {
            "mpanMprn": "<string>",
            "meterSerialNumber": "<string>",
            "consumption": {
              "total": 123,
              "unit": "kWh"
            },
            "charges": [
              {
                "description": "<string>",
                "chargeStartDate": "2023-12-25",
                "chargeEndDate": "2023-12-25",
                "startReading": 123,
                "endReading": 123,
                "quantity": 123,
                "unit": "<string>",
                "rate": 123,
                "rateUnit": "<string>",
                "vatRate": 123,
                "netAmount": 123,
                "totalAmount": 123
              }
            ],
            "meterReadings": [
              {
                "date": "2023-12-25",
                "reading": "<string>",
                "unit": "<string>"
              }
            ]
          }
        ]
      }
    ]
  }
]