A similar thing happened to my sister and I when we went for a day trip out of Barcelona to Girona. It was near a cathedral and there were a few women standing around. They were holding out sprigs of rosemary and offering it to people.
As we walked past them, they smiled and said “hola” and offered my sister a sprig of rosemary. My sister took it and they said it cost 10 euros. Thinking it was nonsense, my sister threw the rosemary back at the woman, who became really fierce and started yelling and screaming at us.
We decided to walk away but they started chasing us. My sister turned around and screamed back at them and we walked on, never looking back. Thankfully the women stopped there!