This is a scammer. They are trying to get you to call them back so you can be billed for the call. If you have a service like mine, you can not call the number back as numbers like this that charge $$$ per minute are blocked.
I get a lot of calls and no one answers when I answer. There is a phone scam going on right now in my area. Someone calls you but do not answer back when you answer. If you call the number back you are charged a $19.95 fee for calling back to see who called you. Wondering if this what's going on.