I used Google Voice.  I had my foods students tell me whether they wanted to have any changes made to their lab groups and if they were having any problems in their groups.  I thought it would be a way they could talk to me without worrying about other students hearing them. 
It was okay.  Some of the written responses were hard to decipher.  I could not understand some of the voice messages.  It took longer to go through all of the messages than it would have taken to go through written responses.  The thing that bothered me the most was having my cell phone ring so often.  Perhaps I can make changes to avoid this.  I would like for the messages to just go to gmail.
Here is a link to a good message: https://www.google.com/voice/fm/03424515620539946930/AHwOX_AvPAKNzYW2ijQHqLrxQ0gqQYwuo2A_2ZgeETT-Qi0mP2Z0-xXFZLVYv4SGkp8kqk6LyKDJekNnBq-8RByzk_Mp9pZSiIaHWdWIR24yaaJlqXKsAu2x4xk1v8Z51VkD2C8n0PSHt5pNOquBHcPI9muo3jtwvQ