We arrived late at night, but the staff already send us key code to get to the building, and there was an anvelope waiting for us so we can get to our beds.
We paid for two beds, but there was only one bed free in the room, fortunately I was with my girlfriend so we shared our bed, next morning we went to tell the staff about our missing bed, and she said it was was their mistake, and that they were fully booked for tonight again.
Also She kindly offered us 50% return of what we paid for our stay and we took that deal.
Altogether it was a nice Stay, the hostel is pretty Big and cozy. We Had a good time and it was pretty cheap for Stockholm. Recommend.