Wrong repairing of stl

Hey
I have a problem with the way Z-SUITE repairs stl-files.
The problem is that I have my stl-file, but when i import it in Z-SUITE it auto repairs the file, this is normally not a problem, but this time Z-SUITE messes the stl-file up when it repairs it.
Instead I can import the file without repairing it, which shows the stl-file how i drew it, but this is also a problem since I then only will be able to print the shell which is a problem because i need the print to be strong.
Is there any way to fix this problem?

This is what is looks like when Z-SUITE repairs the stl-file.

And this is what it should look like, and how it looks if the stl-file is imported without repairing.

Hi,

Can you provide the .stl file, please?

No, sorry i can´t.
I just changed the drawing, and now it works fine.
thanks anyways though.