Voice mail not working on Samsung S9 since I transferred to Xfinity?

I have a Samsung Galaxy S9 and since I transferred to Xfinity, my original phone voice mail doesn't work or push notification, so I have to dial in myself frequently to check on any missed voice mail. I installed Xfinity voicemail and turned-on notifications, but it doesn't work most of the time and especially the audio script, so I have no way to find out what was the voice mail is about?  How can I get notifications when a new voicemail is available? I have missed several messages not realizing that no notifications are being generated.