Got 2 calls on Fourth of July, of all days...Left no message. Looked up the number and its a Mexican/Spanish furniture store from California. Really annoying and weird.
Called and ask if I was "Bob" then hung up when I confirmed. Called back and asked who the were and they said they were a furniture store. Heavy accent and hard to understand. As others sain, weird as I have no business with them.
Now they know Bob is the name that goes along with the number. Resell it, possible pests in the future will shock you by already knowing who are. It's better not to return calls to unknown numbers, either.