So I have a Gamo air revolver( I know not a firearm bit this category seemed most appropriate). I was firing it and on one of the DA trigger pulls, the trigger stayed all the way back. I can push it forward but it won't reset automatically, just when I push it forward. If I pull the hammer back it has an extremely light hair trigger pull and the hammer is very light to pull back. Also if I fire SA the trigger doesn't go forward either. It acts like a Single Action Only. Any suggestions on what to do?