One answer or question I am looking for ....You sue  you win fine .. next sticker ..they do the same .. again you sue you win.
Sooner or later someone goes out of business & starts all over.
What I am looking for, you stated you are losing 50% from this low life copy cat 
What is this can't do by themselves doing  to take away sales of 50%  that you are not doing well that they seem to be doing well besides  being a copy cat ..fair question.
& by the way if they have to copy everything you do to make a living  you should have nothing to worry about  since you will come up with the better mouse trap 1st, 2nd, 3rd & each time and that is how you make a better living, your employees would rather work with you then them, your banker will be happy with you not them, sooner or later you totally win.
Another option instead of lawsuits ..just buy them out  add  a non-compete clause.