Why is my part not going up? Do I need to use CFrame?

Here is my script:

while true do
	wait(math.random(2.5, 8.5))
	while not script.Parent.Position.Y == 53.5 do
		script.Parent.Position = Vector3.new(script.Parent.Position.X, script.Parent.Position.Y  + 0.5, script.Parent.Position.Z)
	end
	wait(math.random(2.5, 8.5))
	while not script.Parent.Position.Y == 28.5 do
		script.Parent.Position = Vector3.new(script.Parent.Position.X, script.Parent.Position.Y  - 0.5, script.Parent.Position.Z)
	end
end

Please fix it.

What your problem is that you have multiple while loops. A while loop goes on infinitely unless you use break to stop the loop.The solution to this problem is to include if statements instead of while loops.

math.randomseed(tick()) -- Truly makes randomizers truly random
while wait() do -- waits 1/30th of a second then,does the rest
    wait(math.random(2.5, 8.5))
    if not script.Parent.Position.Y == 53.5 do
        script.Parent.Position = Vector3.new(script.Parent.Position.X, script.Parent.Position.Y  + 0.5, script.Parent.Position.Z)
    end
    wait(math.random(2.5, 8.5))
    if not script.Parent.Position.Y == 28.5 do
        script.Parent.Position = Vector3.new(script.Parent.Position.X, script.Parent.Position.Y  - 0.5, 
script.Parent.Position.Z)
    end
end