Hi - my current client's fitbit broke off during a walk. I messaged the owner right away to let her know. Thoughts on how to best rectify or not?

Hi there, it's my 2nd time watching a yorkie who wears a doggie fitbit. On first visit, the fitbit fell off. But on our second (current) visit, the leash got caught and snapped off the fit bit from the holder. A piece broke off so I'm unable to re-attach. I told the owner via text and she is bummed (understandably). It was an accident, but wondering if I should offer to take off charges for one night? Or offer "discount" on future stay? Not sure how best to handle since it was a simple mishap. Has anyone else encountered this issue before?