sprint to tmobile migration issues.

Over the weekend my girlfriend and I migrated from Sprint to Tmobile. I got a new phone and she kept her Samsung Galaxy S8. She sent me a text telling me and I quote, "My Amazon app is gone Multiple voicemail notifications, but no voicemail random texts that seem like voicemail to text notifications." She followed it up with a screensht to show that one of her apps was completely Uninstalled. Is there any reason this would be caused by after migrating? Gracias.