You send them a polite email.

"Dear BFL team,

Unfortunately, with the Bitcoin market going crazy concerning regulations and crackdowns on exchanges, I feel uneasy with my investment. In the light of circumstances I would like to request a refund of my order number XYZ1111.

For your future business, I wish you all the best and success. If there are any necessary steps for you for my refund, please let me know so I can accomodate the transfer.

Best regards,
the customer."


Some will say this is unbelievably polite. I say you want money back from them, so dont be an asshole.