Xoom xoom.com transaction charged even after cancellation , Internet

Hello There,
I am very upset with the Xoom customer service and specially with your transaction cancellation process. I have made two transaction last week on 12/22/2012 on 11:17pm and 11:21pm for an amount of $147 and $149.99 respectively. 
Here are the transaction ID: X061841740709466 & X061800373188626
To do the transfer i used the wrong bank account and also informed the same to a customer service agent by name Karen Mae Sapaden about it at 11:23pm to report the same. So as per my conversation with the CSR, she said the request has been submitted and confirmation will be sent by email. 
Today 12/26/2012, i have seen the transactions worth $147 & 149.99 on my account even after cancellation request which in turn resulted in -$70 service charge because of insufficient funds caused by unwanted transaction by xoom. When i called the customer service with the above concern they just say that i am responsible for all the transactions including $147, $149.99 and -$70. 
This has been a very unfair business practice by Xoom and even after my immediate proactive request to cancel my transaction they still processed the transaction without my consent. Thus i need justification in the above case of unfair/ unethical business practice byXOOM.COM at the earliest.