I had the same problem with putting it together. The little warning sticker on the lever isn't much good when the damn thing fires off as you're lifting the seat out of the box. Got a cracking bruise on my right wrist.
Also managed to put the stand on backwards. Didn't realise until I sat in the completed chair. It rocked forward instead of back
Can't see me returning mine. Just sold the PS4 to pay for it (hasn't been on for a year). And likewise, my back is much better already. Amazing how much difference decent lumbar support makes in a few days.