ah right.
the actuator could be set rong, the spring could be too strong, or it could be fucked.
maybes its jammed up, can say as i havent seen it, but if you take the rod off the waste gate, you should be able to pull the rod outward, there will be resistance, how much depends on the actuator spring pressure

if you can pull it out what so ever, see if it needs pushing in as it might of jammed out, but if it has, it shouldn't have so a new one may be needed.

these are just ideas as to what it could be though, ive not seen the car etc so dont go buying a new one unless you deffo need it