To all of you who say that Bitcoin shouldn't be regulated - this is what it results in.
If it was any regulated financial deal - say, purchase of stock or Yen - then there are clear rules on how to handle that, namely, you'd be entitled to at least compensation for any decrease between the 'locked' price at the agreed settlement date and the real settlement, whenever it may happen, and the interest for the period. Repeated such situations would result in a rapid audit to verify if they really have enough assets to pay out all their debts, and if not, shut them down immediately.
Now you're quite screwed, while coinbase has taken a profit on this (and probably other) deals by delaying these settlements. And what are you going to do if you don't get all the losses covered? Your options are quite limited.