I have noticed a bug. The in-game message when you hover your mouse over the call-a-friend button says that you can call upon a friend to assist you once every five days. However, for the last three weeks, I have only been able to use my friends once every seven days, or once a week. Why is this happening?
 "Bush Whacker 2"){kind=icon}
 "Whiteboard Tower Defense"){kind=icon}