My airsoft gun isn't working, can anybody help?

I have a Bravo polymer M4, I bought it from Evike.com last week. When I received it, it had a massive spider in it. Like it looked like a wolf spider. After I killed that, I picked up the gun, which had the wrong part of the butt stock. We called and figured out the stock. Now, however, the gun doesn't fire it's shots. I hear the gun sound fire just like it's supposed to but the shots don't come out, unless I lean it forward, although the shots just roll out. If anybody can help me that would be great thank you. I never dropped it or anything and I'm kind of mad about it.