I had a issue with the same thing and have a ticket to fix it (althought that ticket hasnt been fixed since release.) I had intended to look at a item and ctrl clicked and it bought the item. Unforchantly for me it was 25,000 credits. Never before in any other mmo has this happened to a point where I felt i should put a ticket in. The purchase system needs a few simple fixes.
1. badge items and other high value items should confirm, incase of lag double click or misclicking due to being used to other games.
2. fair resell value on items you bought but couldnt use, like a chest. give full value if it wasnt worn because that will save you so many tickets in the future