Without seeing what you have I'm guessing you need three pieces. A threaded rod that connects the piston with the bolt, The piston and the spring. Here is a pic or two or mine and a pic of exploded view.
I can help you tune it if needed. Start out buy purchasing some aftermarket mags. I use A E Swede. Typically people get frustrated when they try to fix it and it only gets worse. Many times though it is an accumulation of small issues . New mags is a good start. I have 4 Semi-Auto AEA's and all are shoot-able when I want to shoot one. I have other PCP's but I truly like the AR feel and power of these small auto's. I find myself shooting one of them 95 percent of my time. Keeps us up to date on how it goes and feel free to ask questions.
View attachment 537184 View attachment 537185 View attachment 537187