I have recently been inundated with 2216 and 2616 sets where the digit 8 and some with the digit 0 just quit working. It is definitely the set as when a new one in put in it works fine. Is there and documentation showing that these sets have a tendency to go bad in that area of the dial pad? Has any one else had this issue or know what coud be cauing it other than usage over time or a user pounding on the dial pad?