Charge R400 extra on an online transaction

I made a purchase from a UK based online shop. As soon as the order was confirmed, I received an SMS from Standard Bank stating that a certain Rand value was deducted from my account, which was about R400 more than the going exchange rate. Even with any possible extra fees than could be charged as per the Standard Bank website, the amount is still significantly more.<br> <br> Upon phoning Standard Bank to verify the problem and how to correct it, I was given an option to either reverse the whole transaction, which would mean I lose the purchase, or I would have to wait until the merchant banks the transaction before I can dispute the matter. When I asked when an SMS notification is usually sent, the explanation that I received meant that the merchant had already banked the transaction, as that is the only times when an SMS will be sent. Therefore, the dispute process could already have been put into progress, as the transaction was by all indications banked by the merchant and my account debited.<br> <br> After a 32 minute phone call, I requested that Standard Bank phone me back with further information. As yet, I have not had any response from them regarding further information or a resolution.