Reasonable lag time to fire a contractor?

Hi all – I am having some work done – two jobs. The payment arrangement is half up front, other half upon completion. I also purchased the material for the second job (building a fence) but the materials have not been delivered yet.

We met Saturday and they completed the first job Monday. I called Tuesday morning to make arrangements to have the material delivered for the second job (they have to be there Friday to receive and I needed to confirm that they would be). No answer so I left a message to call back and let me know so I could give the go-ahead for delivery (they won’t deliver unattended, nor would I want them to, but they would charge again for delivery if no one is there and they have to come back).

It’s now Thursday ~noon and I’m wondering what’s going on. I called them again Wednesday and today, and nothing.
I need to let the delivery people know today if I need to cancel/postpone.

I’m thinking this lack of communication is enough to go ahead and seek new labor for the job, but I wanted to get more input since I am new to this type of stuff. The money I have paid already covered the flooring so I am not out anything (except a house key! grrr!).

I can’t find anything about them via the BBB. Is it safe to just assume they’re not completing it and to cancel the order? My feeling is “screw them!” it’s been quite a while with no contact, but then I think “what if something happened, blah blah blah.”

Has anyone had experiences with contractors and what is appropriate/acceptable? TIA