Why Does Comcast Hate Me?

What do I have to do to get my digital cable service fixed to work correctly? Why don't you want to fix it? In OCt. we made the to move to digital cable and it is horrible...we have never had decent reception and it has gotten progressively worse...most of the time we do not have channels above 74 and about 50% of the time we only have channels 2-12...starting in Dec. techs have been coming out and replaced everything from the pole to our TV and even exchanged boxes...the real problem(which several techs have pointed out, but no one seems to want to fix) is a bit of tree that at one time grew around the cable...the tree is long gone, but a bit of wood is still on the wire...it did not affect our analogue reception, but is preventing us from getting any kind of decent recption digitally...Comcast has known this for a couple of months now and refuse to fix it. we have been Comcast customers for over 20 years, that means the main line is that old...why won't they replace it? What have I done to deserve this?