KP-05 Magazine probs

[Paul55]

I recently bought a KP-05 Hi Capa that came with 3 x Co2 mags & I x Green Gas mag. Here the problem, one of the Co2 mags works fine, of the other two one only gives weak shots. The other goes full auto & vents as soon as it's put in & fired. The Green Gas mag won't fill up. I get a handful of shots per fill. Any ideas guys? I hope so as this is driving me cuckoo.