Unlike others (and I was quite worried when I couldn't find a customer service phone number as well, which is how I cam upon these reviews), I am very satisfied with my most recent, and first encounter with them.
I purchased a voucher which I could not use (scheduling conflict with my travel mate), and contacted them via their contact form requesting a refund. After doing so I got a "due to high volume you may not hear in 3-4 days". I thought I was about to be another negative review of them.
Therefore I was very surprised to hear in 5 hours that the voucher was canceled at my request, and a refund applied to my credit card (yes, no credits, no restrictions, a refund). All this very politely worded, and almost apologetic.
I'll go back to them with no hesitation.