I got 3 calls no message and when I answered they said nothing

Just two calls one minute apart and no voicemails. After signing up for some "free" contests I've been receiving calls like this and calls from other states the last past week. I have to continuously block them.

They claim to be from the Bridgeport Health Department and said that they received a call that someone in the house had mobility issues. I said absolutely not and where did they get this number. They then hung up.