Sounds like the card issuing bank may have put an authorization hold for that transaction. That extra charge is actually just a hold that is applied to your account by the card issuing bank, it is up to your customer's card issuing bank to drop that charge off of your customer's statement.
While we can't speak specifically about any transactions over the community, as it is a public platform, feel free to give us a call and our Support Team can look at this transaction specifically. If you have any trouble getting ahold of us, check out this thread.
