Unable to Fetch Voicemails in CDR API to get voicemail files using REC API


I’m using this documentation here, and also using HTTPS API for voicemail. Issue is when I fetch all the phone records using CDR API, it is fetching all the records, but if there is a voicemail, it is not pulling out the filename of the voicemail. I know voice mails are getting saved somewhere, but couldn’t find the filename. Filename comes in a record json object and key value pair is ’ “recordfiles”: '"" '. This “recordfiles” attribute is empty. And I’m stuck in it