I answered with "Hello, this is my name.". Silence. "Hello?" Silence. "Hello?" Silence again, then a recorded sounding voice. "Hi, my name is Michael and I'm with the National Health Insurance....." and I hung up.
Robocall scam. Probably a phishing expedition (attempt to gain info that can be used to rob you). Robocalls are illegal — so are calls to my DO-not-call number — and not used by legitimate companies. No one answers if you call back, another indication that this isn't a real business. I played along with the prompts until they realized I was turning the tables, seeking info on them and then they hung up.