We've been getting the same call every day. It is a SCAM and do not press any buttons. This was on the news recently and is apparently being run by some international crooks as a way to put a phony charge on your phone bill. It's been showing on our phone as 408 352 5000, but sometimes shows up as something different. I'm getting ready to call the phone company to see if I can have it blocked.
408 is a San Jose, CA number. I received 10+ calls from them, and they all left the same message: for customer service, press 5, to refuse this pre-paid call press 1, to prevent calls, press 6, to report as harrassing telephone call, press 8. I answered twice and heard nothing, so assumed it was some kind of scam. I get a call about 5 minutes after the last call and my best friend said he'd been trying to call me for the last 5 hours from a holding cell. It's not a scam, it really is the main jail in San Jose.