Worst cad application

I am sorry to say this, but I think this is the worst cad program I have ever used. Every time I want to open an auto cad drawing it crashes. When I am opening a Dxf file instead, it shows only half of the walls. You cannot edit anything in an auto cad drawing. I am very disappointed and would like to have my money back.

Frank 2010 about CARTOMAP CAD