I keep getting spam emails from "headlines@tribxxxx" where the x's are changed to different characters with each message. When these messages first started arriving, the part represented by the x's was always the same, i.e. "live". However, when I blocked the domain in Thunderbird, that is when the addresses started changing each time, it's as if they became aware that they were being blocked! Is there any way of blocking them either at Virgin Media or Thunderbird?