Has anyone had issues with door Internet sellers using signal blockers? Are there any documented similar complaints?

A few minutes ago we noticed the Internet acting up which was the first time we’ve ever had any issues with it in 16 years. My husband was getting really frustrated and annoyed because Netflix was freezing. Then my kids said someone was at the door. It was EE selling internet. I said no thank you and started to close the door and they said in a really smarmy tone “you’re not having any issues with the Internet right now are you?”. I just thought that was odd. As soon as they walked away, the internet was fine. My daughter said they were outside talking for a few minutes and said they had heard there was issues in the area to her. Just wondering if anyone has had any similar issues?