I have the same problem as the OP. I tried doing the "delete all CICAL service books" deal, but there's no service book for the "Device Default" calendar.
So, how do I delete everything in the Device Default calendar? There's hundreds of appointments in there and they all appear to be duplicates of the ones in my Desktop calendar?
Verizon 8130 (on the bench, now
Verizon 9530 (replaced by VZW 4 times, then with a 9550)