curl --request POST \
  --url https://api.example.com/scheduled-calls/customer/{customerId}/cancel-all \
  --header 'X-API-Key: <api-key>'

{
  "canceledCount": 123,
  "scheduledCalls": [
    {
      "id": "<string>",
      "customerId": "<string>",
      "scheduledTime": "<string>",
      "status": "<string>",
      "callId": "<string>",
      "postProcessingFlags": [
        "<string>"
      ]
    }
  ]
}