according to the help link on buy.com:

"Note: if you do not see a cancel button, your order is being prepared for shipment and may no longer be cancelled by you or our customer service department."

I do not see a cancel button anymore and just notice that today....?

Gave me an option to cancel every day for the past 4 weeks to cancel it (yes I literally looked up my order everyday since im obsessed) so it might be a sign