Didn't D* 's contractor put it up there in the first place ?
They should have no problem getting up there to re aim it if thats the case.
Personally I would ask them to take it off the roof, tell them that you cannot get to it to clean it off if nessasary (snow).
Tell them to patch the roof for you Correctly, and move it to a better location on a pole on the ground (if acceptable for you, and if there is a clear openning).
Don't be pissed with D*, remember 90% of the installs are contractors, maybe more.
So the missed appointments are not nessasrialy D* fault, but thier contractors, give them a call as well.
The beginning of your post sounded like we were going into therapy
Make a few calls, get this straightnened out and let us know how you did.
Jimbo