A large number of pilot deviations (or perhaps violations is the correct term) occur because pilots admit fault over the radio and/or on the phone during a follow-up call. If you're off altitude and asked to verify altitude, just say the altitude you're supposed to be at... "Let me recycle my Mode C for you" (of course it's magically working right when it turns back on ).

On another note... there's no need to call the number they give you. Call your attorney instead.