I've had this problem where the arms were installed wrong.
At the base of each arm is a plastic covering, much like the ones you find at the base of a toilet covering the toilet bolts. Slide a thin screw driver there and pop it off (you may not have the covers anymore if the person who worked on it didnt replace them).
Then get a socket wrench and remove the nut holding the arm. As you can see then, you can rotate the arms any which way to the proper park position.
I removed the arms, turned on the wiper switch and turned it off and now the mechanism holding the arms should be in the parked position.
Then place the arms back onto the bolt the way you want them when they are not in use (PARKED). Replace the bolt and replace the covers. Test the swing and park by turning on the wipers. Any clunking and you parked them too tight. If they hit the edge of the windshield, you parked them too far.
Hope that helps.