Tone G 28

i have a dragun tes marker that i bought a few years back. it has harldy been used and worked fine until recently when i took up paintballing again. i fixed a small co2 leak where the expansion chamber is but i still have to recock the gun everytime i shoot. can anyone tell me what the problem is?

is the gun worth fixing and selling? i guess OGI is out of business now so what would my marker be worth?

any help is appreciated, thanks