yes Dish can do whatever they want, but as long as you have all your pics and docs in order as proof, then you have nothing to worry about but, you must notify Dish first before you proceed, so that they are aware of the situation at hand. They do not want bad publicity. There is an absolute order in doing this process or you will get screwed
1st: try and deal with contractor (if all fails, goto #2)
2nd: notify dish of your intent to lien (it usually stops here)
3rd: file your liens
P.S. If you do not take pics of your own jobs as proof, you take away a big piece of your leveraging tool