Cracked (From Top to Bottom)

As opposed from side to side I suppose.  (if you look very closely you can just see the crack - highlighted by the tea stain (a further disappointment)).This was very disappointing. I put my Earl Grey teabag into my lovely Dunoon mug and poured on the boiling water. There was a crack and the very hot water promptly started running out of the bottom of the mug. I have rung and now emailed their customer services department to see what they may or may not say.