Have they sent you the turbo back to you with your old actuator on, or a new one ?

If it's a new one, then it sounds like either it's a different spec, or your old one was getting tired. Lengthen the shaft to decrease the boost. Do this by cracking the locknut off, then remove the actuator from the wastegate arm and give the end fitting a couple of turns, then re-assemble and see what the boost is.