Failing Cable connection.

[Jojo]

Whilst I'm subscribed to 2meg broadband on VM, I noticed I would get a drop in bandwidth at certain times of the day, and sometimes would even struggle to surf the web at all, which has led me to this forum to ask questions and I have since got myself an SB5100 with 20meg connection. Now I always thought the connection was a bit unstable being a forced config, but I never thought much about it, as it would return after 30 minutes or so. But today, the 20meg connection went totally dead, so I went back to my subbed 2meg modem and nothing neither.... ok I thought, I still have wireless on my laptop, and my neighbours both have unsecured wireless access, but whilst I could connect to their routers, their internet was dead also, so clearly, the whole network was down temporarily. Is this a normal thing to happen for cable internet, or should I call VM and let them know of the problems I'm experiencing since I subscribe to the service?
It's happened more than once, which has led me to make this post, and the clever bods at VM charge me to make any call regarding internet issues, which is annoying.