it happened again - another transaction failure

Here is what the customer stated:

"I need a little help with an electronic purchase I tried to make on your website yesterday.
What occurred is I tried to make an electronic payment via Visa Card to purchase some Mp3’s and after pressing confirm or proceed,
The webpage said the transaction failed… I did try the process twice in short intervals so it therefore makes sence that the money came off twice.
My bank emailed me two references to say that the money has been allocated See attached."