I keep getting calls from this number. When I check voice mail I either get a pre-recorded message telling me to call the number (plus an extension, which I keep forgetting to wrote down) or I get a few syllables from a partial word or phrase. Who ever this is, they are obviously hiding their identity.
If they ever want me to call them back they are going to have to prove that they are legit. So far, it just looks like they are your typical scumbags who get a number off a list somewhere and use it to irritate people at random hours throughout the day.