I know. But I honestly read that as sort of a formal disclaimer, in the rare exception something goes wrong. Like I said, I bought gems before and they were delivered instantly. It's what I expect. "May take up to" leaves a lot of room. Many companies use that phrasing.
They are not in the wrong, I just think they can communicate better if they want to. There's quite a few topics about this from frustrated customers, and it can be easily avoided with a clear message. I've read that had I bought the gems separately, it would have been different. That's annoying. Be clear about that.