Development delays happen and are perfectly normal. I'm a software engineer and my projects only get delayed whenever the stakeholders flake out and don't get back to me in a timely manner despite my prodding them via email with our managers CC-ed.
I feel your pain... you should email them a virus to give you remote control over their machines, then send them messages "from God" telling them to reply to you. And give you a raise. And maybe some candy.
