The details of what happened are not in question here. The issue at hand is HashFast agreeing to refund cancelled orders with BTC, and then refusing to honor that agreement. Simon Barber (Founder of HashFast) was asked by cycloid on the 10th of August 2013 if refunds would be in BTC.
He clearly asked in this post
https://bitcointalk.org/index.php?topic=270384.msg2903196#msg2903196"Now since the only payment option is in BTC Will I get the same ammount of BTC back should you fail to deliver by December 31st?"
"Or are you going to pull BFL and give refunds at exchange equivalent to USD/BTC indexed to the current fiat price per unit?"
Simon Barber's (HashFast's) official response was
https://bitcointalk.org/index.php?topic=270384.msg2903338#msg2903338"Orders are taken in BTC, in the unlikely event we get to refunds they will be given in BTC."
Ok, I was not aware of the context of that statement. The statement itself can still be interpreted in several ways, to continue my analogy, HF could agree to send you another paper cheque so are not forced to get a refund through ACH, paypal or even bitcoin for that matter, but refund using the same manner you paid; however given the question he was answering to, thats difficult to argue now.