curl --request GET \
  --url https://api.maesn.dev/accounting/customers/{contactId} \
  --header 'X-ACCOUNT-KEY: <x-account-key>' \
  --header 'X-API-KEY: <x-api-key>'

{
  "meta": {
    "warnings": [
      "Field not used by target system"
    ],
    "pagination": {
      "total": 123,
      "perPage": 123,
      "currentPage": 123,
      "totalPages": 123
    }
  },
  "data": {
    "id": "92c4f3a2-5b8e-4d1b-8a0c-9f6e7d2f3e4b",
    "addresses": [
      {
        "addressLine1": "Lucky street 1",
        "addressLine2": "2nd floor",
        "city": "Berlin",
        "countryCode": "DE",
        "postalCode": "10243",
        "type": "BILLING"
      }
    ],
    "companyName": "maesn",
    "contactType": "CONTACT_PERSON",
    "contactPersons": [
      {
        "emailAddresses": [
          {
            "email": "john.doe@company.com",
            "type": "BUSINESS"
          }
        ],
        "firstName": "John",
        "lastName": "Doe",
        "phoneNumbers": [
          {
            "number": "+49 7163307056",
            "type": "MOBILE"
          }
        ],
        "salutation": "Mr"
      }
    ],
    "documentId": "Z1248601M",
    "emailAddresses": [
      {
        "email": "john.doe@company.com",
        "type": "BUSINESS"
      }
    ],
    "number": "1042",
    "phoneNumbers": [
      {
        "number": "+49 7163307056",
        "type": "MOBILE"
      }
    ],
    "projectId": "3",
    "updatedDate": "2018-01-01T13:00:00.000Z",
    "vatId": "DE123456789"
  }
}