Hi,
Duplicated SMS is caused by intermittent Internet connection or the app itself is not updated. We recommend using the WSReset command to clear the store app’s cache and reset it to a clean state (This also applies to built-in apps of Windows 10). To do so, follow the steps below:
- Press Windows + R to open the Run window.
- Type in WSReset.exe, then click OK.
- Wait for the command to finish.
In addition, you can visit this link: Run the troubleshooter for Windows apps to perform diagnostics for Microsoft Store and its app by running the troubleshooter.
Make sure that you have log in your Microsoft account to authorize your computer to accept apps from our store.
For best results, you may uninstall this app and redownload it from the Microsoft Store. To download it, visit this link: Microsoft Messaging.
Let us know how it would go after clearing the cache.