I have been left several messages from this number as well. I have a long intro on my voice mail so usually the first part of their message is cut off but it does say "This is an important business matter and you must call us by 9:00PM Standard Central Time." I've called back to see what they want but no one ever answers.
I was just left a message on my answering machine. The message was cut off at the beginning and the male caller said that they couldn't explain the purpose of the call on an answering machine and that it was an important matter. He said to call (281)647-4152 and to call back before 9:00 P.M. Central Stander(?) Time. I looked up the area code on my computer and saw that it was Texas, (I'm in New York City). Then I googled the entire phone number and found this complaint thread. I haven't called them back.