How do I get the voicemail transcription from a Group using C#

First I am unable to get even my own personal voicemail transcriptions using this method. It find the transcription record but I can't see any parameters with the transcription string.

Second how will I change this to access a Group's voicemail transcription?

Thanks.

using System;
using System.Threading.Tasks;
using RingCentral;

namespace Account
{
    class Account
    {
        static String SERVER_URL = "https://platform.ringcentral.com";
        static String CLIENT_ID = "************";
        static String CLIENT_SECRET = "********";
        static String JWT_TOKEN = "************";    

        static RestClient restClient;

        static void Main(string[] args)
        {
            restClient = new RestClient(CLIENT_ID, CLIENT_SECRET, true, "VoiceMailTranscriptionGet");
            restClient.Authorize(JWT_TOKEN).Wait();
            GetMessage().Wait();
        }



        static private async Task GetMessage()
        {
            ListMessagesParameters parameters = new ListMessagesParameters();
            parameters.messageType = new String[] { "VoiceMail" };
            var response = await restClient.Restapi().Account().Extension().MessageStore().List(parameters);
            foreach (GetMessageInfoResponse record in response.records)
            {
                if (record.attachments != null)
                {
                    foreach (var attachment in record.attachments)
                    {
                        var fileName = "./src/test/resources/" + record.attachments[0].id + "_voicemail.txt";
                        if (attachment.type == "AudioTranscription")
                        {
                            var res = restClient.Restapi().Account().Extension().MessageStore(record.id.ToString()).Content(attachment.id.ToString()).Get();
                            //Path path = Paths.get(fileName);
                            //Files.write(path, res);
                        }
                    }
                }
            }
        }
    }
}