Bests & Worsts Reviews from Amazon

I bought this chair in May of last year. I assembled it myself, following the instructions provided, and I was proud of it. The chair offered me a lot of support, and was very comfortable...Until it wasn't. Because about three weeks ago, I noticed that whenever I'd sit down on the chair, I'd gradually start sliding off. And eventually the back of the seat itself would start to lean forward. It completely threw off my equilibrium, but I couldn't find out why. It started to become a hazard. The chair wasn't sturdy as it used to be. It felt unbalanced, and it would creak, moan, and pop with movement. I was afraid the chair would collapse any moment. So I finally decided to take it out of my room, and examine it more closely. That's when I noticed that a rod by the gas pump was bent. And it actually bent the casing with it. How the hell does this happen to a chair that I haven't even owned for a year? I checked the specifications on Amazon. I mean, maybe I somehow exceeded the weight capacity, although I seriously doubted it. And I was right. I was nowhere near the maximum weight capacity. I never abused the chair, stood on it, or put heavy objects on it. And I followed the schematics correctly. Why did this happen? I contacted the seller, and their solution was to send me new parts, specifically a new gas cylinder and plastic covering. Well the cylinder just failed to deliver. It was damaged in shipping, so I had to ask for another. Then when I finally got it, I attempted to install it only to realize I couldn't. The cylinder they sent me simply was not compatible with this chair. There's supposed to a rod that connects the cylinder to the chair base, but there isn't one. What's more, there aren't even any screws that would allow me to remove the old cylinder from the seat. Honestly, this chair is a nightmare. Everything I've gotten from Amazon has been top notch quality. But this chair is just defective, and it's unfixable. And the seller refuses to give me any compensation. They did offer a refund of $50, though. But really? $50? I paid $170 for this chair, not including taxes and the price to ship the damn thing.