Is it possible to restore deleted recording
To save your recordings the app relies on the local device storage. When you delete a recording, an associated file will also be deleted to free up space. Because of privacy concerns, the app does not sync your recordings to the cloud nor makes any backups on its own. It's solely a user's responsibility to make these arrangements to protect their data.
To put things short, no, there's no way to restore deleted recordings back in the app. But if it's really vital for you to get it back, the only thing we could think of is to try some Data restoration software for Android on your own risk, or hire a reputable Data Recovery service (it may be costly).