I had it happen to my red and orange ones. I emailed them and they replaced them straight away - I asked for different colours though! I've got heaps of Itti's and these are the only ones I've had trouble with.
I know awhile ago they had a real backlog of emails due to orders from the Baby Expo's, so it might be worth calling them directly. They replaced mine even before I had sent the 'broken' ones back, so I am thinking it might be a common problem. I thought they might of wanted to check mine out first to see if I had done something to them to damage them.