Even during Covid doorstop sharks are still out and about targeting older people in particular saying that they are paying to much for their utility bills. Reminds me of the time this happened to me. The man at my door said he had documentation showing that I was paying to much for my gas bill. I asked to see the paperwork and he declined so I told him that it was a breach of data protection as the information was personal to me. He could see he was not getting anywhere with me and suddenly stepped forward and put his foot in the door preventing me from closing it. I shouted loudly "get your f!!!!!! foot out of my door". I don't know who was most shocked him or me as it is not a word that is usually in my vocabulary. Anyway it did the trick as he stepped back and I slammed the door shut. Not advocating this as a means of dealing with such people but just be wary of anyone like this knocking at your door.