I've done a fair amount of complaining about Cryptic on this blog, so I think it's only fair to also give them credit for doing things right when it happens.
Last week I meant to buy a bundle of Zen, but after the transaction had seemingly gone through, I received an error message saying that it couldn't be processed and when I checked my balance, no new Zen had been added. This led to me trying two more times, just to run into the same error again and again. Ten minutes later I suddenly received three email notifications at once, showing that all three purchase attempts had in fact been successful after all and I'd just spent more than £100 on Zen. Aieee!
I wasn't sure whether this sort of virtual currency was refundable at all, but still decided to open a ticket to explain my problem. Working in e-commerce myself, I'm actually quite understanding of this kind of glitch; the question is how the company deals with customer contacts about it afterwards.
And what do you know, I had a response within a few hours and they happily refunded the duplicate transactions without any fuss. So thanks, Cryptic!