Woman knocking on all doors in a secured apartment building claiming to be with the energy company. Said the bills were incorrect due to a new "green update" the building had made. Said she wanted to check that my bill was correct. Asked to see my bill. When I declined, she was persistent and asked when she could come back. I said I was not willing to discuss with her further. I checked in with my building manager, and they let me know this person was not authorized to be in the building, was not with the energy company and official communication would only be sent out through an email from the building or energy company.