Fake or Real?

I am a new Cox member, it's been only about a month. But I've been getting calls nearly every day this week from a number listed as Cox Communications. The number is 1-877-316-1403. Every time I answer the phone it hangs up after a few seconds. If I recall the number it will identify itself as Cox Communications, tell me to hold for the next agent but them immediately hang up. Is this a real Cox number or is this just something I should block? I have no idea what the purpose of the call would be.