My script won't tweenposition the image in the gui, why?

function onTouch(hit)

	if hit.Parent:FindFirstChild("Humanoid") ~= nil then

		if game.Players:FindFirstChild(hit.Parent.Name) ~= nil then
		local player = game.Players:FindFirstChild(hit.Parent.Name)

			if player:FindFirstChild("PlayerGui"):FindFirstChild("ScreenGui") == nil then
			sg = Instance.new("ScreenGui")
			sg.Parent = player:FindFirstChild("PlayerGui")
			end

		if player.PlayerGui.ScreenGui:FindFirstChild("MessageBox") == nil then

		local f = Instance.new("ImageLabel")
		f.Name = "MessageBox"
		f.Position = UDim2.new(0, -210,0.245, 0)
		f.Size = UDim2.new(0, 320,0.1, 155)		
		f.Image = "rbxassetid://250533638"							
		f.Parent = player.PlayerGui:FindFirstChild("ScreenGui")
        f.BackgroundTransparency = 1

       
        

------------------------------------------
wait(2)
f:TweenPosition(UDim2.new(0, -3,0.245, 0), 'Out' ,'Bounce' 1)



------------------------------------------
wait(10)
		f:Destroy()
		
		end
		end
	end
end

script.Parent.Touched:connect(onTouch)