Well… the docs.blender manual addons import_export scene_dxf clearly tell what is supported and what not. So if your fle uses some features which aren’t supported by the native importer from blender…
This is a general problem with different CAD data which do provide several additional info but a polygon modeler doesn’t… it’s just a different area… so the support of some formats depends on the need of the customers…and you know that blender isn’t sold…
There are some discussion here ( you may find some more with the search feature 
–icon top right )
…suggestion some other tools and and addons; some paid…
…maybe even this