The Nissan Path

I have a black Nissan Pathfinder 450T 2010. Have had it a year and absolutely love it!

That said, after just getting it back from it's 90k km service (the following day) I immediately started getting visible 'dry' moisture pouring out the air conditioning, and the window is steaming up and won't clear with the air con on the screen. I took it back to them and they said it's the heater core under the dash that's leaking. I questioned the timing (a day after a service) and they said it would have been nothing from the service. Is this a fair call?

shouldn't be related, but at only 4yrs old i wouldn't expect a heater core to be leaking.

Heater core replacement is a bit of a pain, as the dash has to be removed to get to it. If it were mine, I would spend an extra $80 and replace the three mode door actuators as they do go bad and the dash has to be removed to replace them as well.