You're getting ads? Make sure you're using the same acocunt on the new device that you used to purchase the app. Check within the app settings to see if there's a "restore purchases" option. There may be a support contact or process in the settings for the app, or you can provide feedback to the developer -
gosmsprofeedback@gmail.com is listed in the Play Store listing for the app.
If you need additional help or have more questions or details to share, please join the site so you can reply in this thread. See
this link for instructions on how to join Android Central.