Like many here, I bought the Joying unit to replace the Alpine. I used the supplied keys to remove the Alpine, and for some reason, the unit only come out half way and jams, with something seemingly locked on the left side. I tried pulling (as hard as I was willing to risk), pushing from behind, and nothing. It doesn’t feel like it’s cables, more like something is still locking the “chassis” to the metal frame. Any ideas?