Door lock problem 330i 2002

The lock cylinder in my driver door was punched in (vandalized). The keyless entry system continued to work, opening driver door lock and all others. My local BMW dealer ordered & installed a new cylinder (charging me $300). After everything was put together again, they informed me that they had discovered that the key would not work in the lock because the lock actuator was damaged, and they want to charge me an additional $380 to replace the actuator. Does this make sense?? If the keyless entry works fine, doesn't that mean the actuator is fine? And even if they're right, should I have to pay so much more for something they failed to diagnose in advance? Thanks for your help....