Can you post a video? If you took it apart and reassembled it but it's still not working I think you should figure out what part is broken (if any) before ordering.
What do you mean by the cocker is not "holding"? Does it not lock back when pulling the trigger in double action or when the hammer is manually cocked back by hand to shoot in single action?
Check for any damages with the hammer spring and strut assembly:
If not assembled correctly or if the strut is too deep then the trigger will have a lot of travel and may prevent trigger from functioning at all or cocking back.