It feels like I'm being trolled.
I did everything by the book, travel insurance valid for a year, solid supporting docs (even though the application centre gave half of them back before sending to the Embassy), signed letters from the boss, and from the inviting company. In those letters it explicitly states that I will have to make multiple trips to the Schengen area.
What could have gone wrong?
What's the point of granting me a multiple-entry visa, if the validity is only for 5 days?
What can I do next time to prevent this?