I had a cart issue as well trying to get a horse one. I had it in my cart for a while and then when I went to check out it said there was -1 in the store. I refreshed it and then it said 0 in the store. It was still in my cart but wouldn’t let me check out. So I took it out of my cart and then it showed one in stock so I re-added it to my cart and it did the same thing. I tried for half an hour taking it out and putting it back and it still wouldn’t let me check out. So I let it go and just got the other ones. I liked them all so it’s okay.