I would write them back and request a refund. That looks to me like rock that was once "live", but no longer is. It looks a lot like the Jakarta live rock I got when I set my tank up. but only in shape, as mine was FULL of life. True live rock has multiple different colors on it. I have attached a picture of Jakarta live rock for comparisonI have just received some live rock from a supplier by mail, and several people have claimed that it's dead or nearly so. They say it won't count as live rock until it has been cured for about a year or so.
The supplier responds:
"It’s clear that some of the bacteria on the surface of the rock may have died during transport. However, the bacteria inside the rock typically survive. In an aquarium under light, live rock eventually develops coralline algae, but in the shop without lights, this algae doesn’t have a chance to grow."
What do you think?