What did their tech support say when you contacted them?
I tried to contact them at the irc channel #tradehill - but no answer. After your post here I wrote an email to them and this apparently worked. They blamed some 'manual verification' for big withdrawals. I don't know maybe I've got a bit too sensitive after mycoin (and bitomat) - but honestly over 12 hours of wait time makes th useless for my operations. Thanks for the suggestion!