We G18c trigger won’t return

[Kirbymeister]

ive got a we G18c and bought it secondhand with a problem. When then gun is cocked the trigger wouldn’t always activate the hammer. I looked this problem up online and was told it was the hammer spring and the hammer itself. I ordered an updated hammer spring, steel hammer and full auto sear etc and fitted them all and now the gun with strike the hammer every time. The problem I now have is after the gun is cocked and you pull the trigger it strikes the hammer as it should but the trigger won’t return. And because of this it vents all the gas after one shot.
From what I’ve seen there is nothing missing or broken inside the gun and I’ve tried looking online for any info that might help but I’m at a loss.