If the spray is only coming out of the nozzle, like it would if you were operating it normally, And there is nothing spraying out anywhere it should not be spraying out, then this should be something you can fix. There should not be a reason to send it in. So please check a few things first.
If you are getting spray our of the nozzle like you would if you were operating the airbrush, but it is happening when you are not pulling the trigger back for paint, then it is one of 3 things.
A. You have moisture in your air. Moist air will spray out even when not pulling the trigger back because the liquid is in the air, not the cup. I have a drier on my compressor, and when it is humid I can still get water in my air.
B. your needle is not seated all the way either because it is not adjusted correctly, or there is gunk in the seat.
C. The seat could be damaged. But this is rare in my experience.
1. Pull the needle out like you are cleaning it. Then pull out the needle seat, and clean it out. Make sure there is nothing inside it.
2. Reassemble and make sure the needle is pushed all the way in. Then tighten the grip.
3. Purge your moisture trap on your compressor. Make sure it is emptied out and you have dry air.
4. Test spray again.
I hope this helps.