conversion into dxf or shp

Hello,

could you please help me to convert m file into dxf (polygon) or shp (polygon). I have used Mapping Toolbox to convert this file into shp, but I could only generate polyline-type shapefile. I do not know how to get polygon-type shapefile. The results for polyline are not good.

Which command would be appropriate to solve this problem?

Thank you.

Regards,

Malgosia