In fact, it is possible to recover deleted data from hard drive, when a file is deleted from hard drive, it doesn't mean that the file has been wiped from , the files system just make a "deleted" flag to the data, whihc make us can't see it as normal. Until new data save to the space where the original data save in, it will be overwritten by new data. therefore, you can try to use iPhone Data Recovery to recover audio recording from iPhone.
To retrieve deleted text messages from iPhone, you have two solutions in general: If you have an iTunes backup, you can restore iPhone lost data from iTunes free. To restore from iTunes backup, you need to launch iTunes on the computer and go to iTunes>Preferences>Devic es. You will see a window with all of your backups listed on it. If you don't have an iTunes or iCloud backup, don't worry. Use some more powerful iPhone Data Recovery especially designed for iPhone.