had one of those a couple of years ago. unit was only 2 or 3 years old. wanted it fixed under warranty. i told her it was her 4 little dogs doing the damage. she didn't believe me that her precious dogs would be able to hit it that high. couple day later she called back in and appologized. let let her dogs out and each one went right on the same spot. she just happened to be on her porch and seen them do it. she put a little fence around the unit.