This happens to some credit cards.

When we authorise your credit card details we verify the validity of the credit card and that it is credit worthy. This is done by a one dollar authorize transaction where one rand is reserved on the card account for a short time, then released.

Most credit card holders never see this because this is a known and recommended practice for credit card validation and so most credit card companies do not display this as a transaction in their bank statements.

 So, in short we have not tried to charge you anything. The one dollar will be released after a few working days (depending on your bank).