PDF imports as bitmap only - but I need vector

Hi. 

A customer sent me this pdf. And when I drang and drop this into Corel, it shows just bitmaps with a bad resolution. 
When importing it in another vector software it shows up as vector file (but looses all parameters... like line thickness, fillings and things like this)

Sometimes corel asks me between two different ways if importing the file, but not this time.

This is the file: 
PDF

And this is how it looked when imorted into corel:


Any ideas to get this as a vector into corel?

Thanks!
Roelli.