.2mm should've been more than enough resolution to get a good result. Whoever printed that for you needs to dial that machine in because there are some real issues with the top and bottom layer both. Supports should not have left any marks on the print itself if they were set properly. As for the pieces not fitting together, that is because the extruder is not calibrated. It is over extruding causing the parts to be larger than expected.
I'm going to see if I can find your stl file here and see if I can generate a better result.
EDIT: I haven't taken the time to learn 'Blender' and the file doesn't open in Fusion 360. If you post the STL I'll be happy to have a gander, but I'm not going to learn blender to to create one