So far it working really well, but I found one part of setting up a bit confusing. After I first set up the app it brought me to the settings page to select my call back number. Since I have only one (my cell) and that number was displayed I thought it was set.
The next few times I launched the app it brought me back to that page. I was confused why cause my number was displayed. Only after a few times did I touch the number and then saw the little green check mark. I guess if I had more than one call back number there would have been a list.
My I suggest if can be done, that if there is only one call back number that it be checked by default or have a bit of instruction on that settings page to let uses know that have to touch to select the number.
Anyway, great work so far!