MalmoSweden,
I suggest a quick call to the Police Assistance line 131444 with the details of the abandoned vehicle would assist in this matter. There are some issues with having an abandoned car towed but your local Police should be able to guide the OC through this process.
Though it is important to clarify where in the car park is the abandoned car parked?
If the car is within an owner’s lot than there is little that the OC can do about this. The owner (if the car is not their’s) should be also able to contact the Police with respect to having the car removed as this is a matter of trespass.