How "early" did you call?
Their posted hours are:
Our office hours are 9am - 8pm Mon-Fri, EST.
Toll Free (North America) 1-866-244-8796
Did you leave a message? It sounds like you did (some people complain about nobody answering, but then that person never even left a message). I would guess that they respond to them in a first-in, first-out order meaning that any messages last night or overnight were getting answered first.
If anything, Axiom is known for their outstanding service. Just keep in mind that you aren't the only person who has probably called in with a need.