I recently got a Samsung Galaxy S7 Edge and I transfered all my purchased songs from iphone.

How did you transfer the song files? Can you locate the files in their directory using My Files or some other file manager app? Chances are that you have duplicates of those music files.
 
And do you see duplicates of any of the files? A duplicate file will usually cause a number to be added in the file name.
 
I'm not familiar with the method you used to transfer your data, but the file was presumably copied twice, either by accident or through a bug in the system.