I am incredibly tired of all the "is it knife time yet?" threads etc so I can only imagine how annoying it is to try to get work done while deluged with them especially when they start actually preventing you from getting the knives out.

You would think some people here were waiting for a kidney rather than a knife.

I have dealt with suppliers and sometimes things happen and deadlines cannot be met. putting a bunch of pressure on them only makes things worse.
All you can do is trust that the people you are working with are doing everything they can and let them know you trust them to get things going as quickly as possible. I have found that when you are reasonable in a situation like that they really go out of their way to show you that your trust is not misplaced.