Take a look here: https://www.macroplant.com/iexplorer/tutorials/how-to-transfer-songs-from-iphone-into-itunes
You will need to use iExplorer in order to do it easily.
If you can take a minute and use the rating system to rate our session as 3 stars or higher and press Submit so I am credited with helping you.
I am sorry to hear that -- I am only a tech on the website. I hope you were able to follow the steps to complete the issue.