Seneca/Sam Yang New user, new gun issues

I just got a refurb Seneca Dragonfly MK2 from Pyramid. I got about 17 shots through it and it stopped shooting. I was able to get the pellet out, but when trying to dry fire it doesn't sound like I am getting any air. When I pump it I notice some air escaping the hole in the underside.
Any ideas on what it could be or if it could be an easy fix?

Another vote to call Pyramyd. They have great customer service. They will take care of you.