Hiya, I sold my son's Jumperoo on Facebook Marketplace a couple of weeks ago. He hasn't bounced in it for a while as he's too big but it's been in his room and he'd always play with the animals and the sounds would go off. I bought it second hand myself then decided to sell it on the save space. Now the girl who bought it from me is saying that the sounds have stopped working and she went to change the batteries and they were all eroded as I'd left them in. My argument was that if the sounds were working when I sold it and have only just stopped then it sounds like just bad timing because at the point of sale it was fine. She's saying the batteries wouldn't have eroded that quickly. I'm pretty sure she wants a refund but I don't really feel like I should have to. I sold the item in good faith. Any advice for dealing with this? Thanks