A customer messages me to say she paid for an order on my shop and then it shows her a message regarding a "security code" error and that the payment didn't go through. The customer calls her bank to confirm if the payment went through or not and they confirm it is charged.
However when I checked I found the order in the abandoned carts which means no payment was received. The customer showed me bank statment with my shop name on it.
So what is this? and how can we avoid that hapening again with other customers?