What does the discussion section have to say on their vendor page? Seems unusual that an order would be cancelled after being confirmed without any explanation so look to see if you are alone or if others have had something similar happen. At the end of the day you got a refund, granted an explanation would be nice but sometimes these things happen and you are left wondering. You can bank the feedback in your order section so there is no rush to leave it, go and see what you can find out first and the report back here.