You will need to start a ticket with support - see KaW Support - Create Ticket
They should be able to help you out. At the least, they can confirm number of packs purchased in a short amount of time (double click, as it were), the type of pack (e.g. double hit), and whether you got the double items. (If you didn't, clearly it's a double charge glitch.)
You can also call your cc company to find out the same. You can file a dispute with them about the charge if it seems to you you have been double charged. The process can take some amount of time (a week? a month?), so be prepared for a wait.
They will tell you though, better / faster to have the vendor reverse the charges / provide a credit - less paperwork back and forth, and so on.
Good luck.