Energy efficiency calls

"Unsolicited home improvement offer linked to energy efficiency. Called stated they were not selling anything but were conducting a,survey to see if,we qualified for government grant towards sustainable energy products. I said not we were not interested and that were were signed up to telephone preference service. Before I could finish my sentence the caller hung up. Very rude. I advise anyone else receiving this call to simply hang up and to not to say anything at all to these contemptible individuals"