Yeah, that's why I gave up on customer service. If you've done every flavor of reset and still have problems, pretty much there are only two things left: known (or soon to be known) software bug, or bad hardware.
So then you're left with the csr trying to convince him/her that (gasp) their software actually has a bug, or you're left trying to convince him/her that you need a new box/smartcard/switch/whatever.
The former is pointless; until they get a lot more reports they don't believe you. And even if they get a lot of reports they sometimes don't, so you might as well wait.
The latter is just painful. I don't know if the 721 is still on their "advanced" list, but it took me 4 months to get them to replace a bad 921 that they admitted was bad, because the only guy who had authority to authorize a swap was apparently out for donuts or getting a pedicure or something.
I'm on my third 921 and fifth or sixth 721, and was just getting to the point where things had been stable for awhile.
In this case, as long as keep getting all the rest of my channels, I'm happy. If it gets fixed, great. If more channels go away, I think I'll finally consider cable.