Not receiving any reward from the snowdown even after 24 h. (the blue poro icon)

I don't think anyone can yell you 'why' with out more info. Best bet though is you failed to meet one of the requirements or there is a lag and needs more time to show up, I've had to wait before up to three days at peak times for icons. http://3.bp.blogspot.com/-Q6MnFdXWIUU/VJAIkpgqwuI/AAAAAAAAgCs/tZErywzw8hs/s1600/icons.jpg If you want to be sure I'd suggest playing more and making sure you tag enemies 5 times with your poro, 'actually count them' and make sure they are hits, use to the king once and win.