curl -X GET 'https://app.yampi.ai/api/v1/accounts/1/contacts?page=1&sort=-last_activity_at' \
  -H 'api_access_token: TU_TOKEN' \
  -H 'Content-Type: application/json'

{
  "payload": [
    {
      "id": 1,
      "name": "Alice",
      "email": "alice@acme.inc",
      "phone_number": "+123456789",
      "thumbnail": "https://...",
      "identifier": "ext-123",
      "last_activity_at": "2026-03-13T10:00:00Z",
      "custom_attributes": {}
    }
  ],
  "meta": { "count": 42 }
}