AngelzOO, if I were you, I'd be on the phone with them letting them know exactly what I thought if my net access was down 6 hours a week. In my second or third month of having my cable modem, I did have problems... I was getting speeds at about a 36.6 modem. So a call was placed to the company... actually both I, and a friend of mine called for me because I kept getting some unintelligent help from their end. Anyway, by the end of the phonecall, my cable modem was free of charge until their new T3 went in (too many ppl, too little bandwith). So for 3 months, I had a slow, but FREE cable modem.
It did suck, but it ended, and then the speed picked up to what it was supposed to be. I'd call and tell them how bad your uptime is and request some sort of compensation for it.