TivoHD + Comcast CableCard + Tivo Support = Lost hours and no solution

Ordered TivoHD recently, and tried to install CableCard into it. It didn't work, and I had to call Tivo support a number of times, including 2 times waiting more then an hour on the phone and giving up, and nobody there really knew why the problem is and what to do with it. They tried to bounce me to cable provider, even though their site directly instructs to call them with the problem, and at the end just gave me quote of some forum posts. Why they need support which knows less than forums users and doesn't even know what their own error codes mean? Why can't they train their support people to be helpful?