Voicemail not working on Samsung S24 Ultra

Voicemail has not worked on my Samsung S24 Ultra since I got it three weeks ago. It has an ESim. The Sim card from my old Note 20 was not returned to me. I have been to the local Xfinity store twice with no solution. They told me to use the native Samsung voicemail app, which doesn't work. Right now the only way I can tell if I have a voicemail is to dial *86, which is unacceptable. I at least need the phone to alert me that there are new voicemail even if I have to call *86 to retrieve them. Please help!!!