Watch the Video Demo :
"I had a number of important voice memos(m4a) and I just deleted them on my iPhone 4. how do I get these back?"
There is an easy way, you can use Dr.Fone (iPhone 4) to directly scan and recover deleted voice memos from your iPhone 4.
Download iPhone 4 Voice Memos Recovery :
[for Windows users] http://www.total-data-recovery.com/iPhone4/
[for Mac users] http://www.total-data-recovery.com/MacOSX/iTunes/