Hard to tell, but still: from your last video, i'd say that it works o.k. like that.
I understand correctly that you just bought this camera? If so, i would certainly return it, or have the seller fix it at his expense.
Even if it works o.k. without prerelease, there still is that prerelease problem.
I don't know how myuch fixing it would cost. For that, talking to a repair person, explaining what's wrong, and seeing if they use fixed fees, and if so what they are, would be the thing to do.