This is not the way to do customer service. If not this incident, I don't know when they start to care me and return me the 64.xxx BTC.
The payment has been successfully completed
http://blockchain.info/tx/cf7121622d6b208357b2a115cc75a9be283f8996dd7d6f612923b30f600bcaddYup the "duplicate" payment has been payed out and thus the amount of 64 BTC was put on hold before user agreed to return the faulty payment. So everything could be solved much faster and easier by contacting support. I suppose it's always a tempting to try to get away with something that not belongs to you.