I created a support ticket as that was the only “after-sale” help that they offer.
But since tickets are slow and chats are fast, I went to “pre-sale” chat and managed to cancel the unwanted order. Hope to see the money on the PP account soon.
Told them about the bug, somehow I don’t think they’ll fix it. I think that the bug is bad use of cookies. And fixing that would be a major modification.