So my rear seats releaser popped up a little bit, mechanism works but this red button doesnt move at all and i cant get it back. How to fix this

On my Mk 2, this used to happen if I didn't really "whack" the seat backrest home. Try releasing it again and whack it hard against the stop when you put it back.....

As above.. it's telling you that the seat backrest isn't locked into position properly so have another go with a bit more force