These fields are missing from the API
Phone: Job Title: Organization:
These are the only fields available in your API.
"email": "string", "givenName": "string", "surname": "string", "status": "WAITING", "registrationDate": "2019-01-15T17:00:00Z", "joinUrl": "string", "confirmationUrl": "string", "registrantKey": "string"
My request to your developers is that you make those other fields available.