Called Century Link earlier today so I don't know if it's related to that or not. Other sites have reported that it may be a call from some overseas Century Link repair call center. Don't know. Comes up on caller ID as "Stream Global Sys".
I opened the line and hung up them without saying a word. They can deal with it or leave a message later. I don't answer unknown callers. And if they call back, I'll block them.
I got this call after I was talking with CenturyLink technical support and my phone ran out of juice. It was the tech I was talking to informing me that they would send a text letting me know when my internet issue was resolved. In my case, it actually was CenturyLink Tech Support.