Whenever I buy anything, it gives the "Oh No! Looks like the page refreshed. You are seeing this message to prevent you from accidentally making a duplicate purchase." Even when I didn't click on it twice?

Personally, that happens to me all the time, usually when buying multiple different items at the same time (ctrll+click). It's an issue with the load time I think. But the item does end up bought and in my inventory. I don't know if you checked if you have the item or not, but in my case, I usually have it just fine.