No message

Call my cell but hang up when answering machine pics up

They call and hang up. I called back and it says it is a "Sweepstakes" company and someone will call back.
I tried to call by blocking my number and it says they "Don't accept blocked numbers." So, they are phishing for something. I don't believe it is really a Sweepstakes entry. I think they are trying to obtain personal info.

This is a telemarketer regarding medical insurance survey

Got this call. Did not answer. No message left. Sure sign of scam.