Dropdown not functioning (close mechanism broke it)?

local black = false

function dondrop()
    if black == false then
script.Parent:TweenPosition(UDim2.new(0.5, 100,0.5, 225), "Out", "Quad", 1)
wait(0.1)
black = true
script.Parent.DonateTitle.TextLabel.Text = "Close Donate"
    elseif black == true then
script.Parent.Position = UDim2.new(0.5, 100,0.5, -500)
black = false
script.Parent.DonateTitle.TextLabel.Text = "Donate"
    end

script.Parent.Parent.Donate.MouseButton1Down:connect(dondrop)

the elseif is supposed to make it so that when it's already dropped down, it will go back up again to the invisible-land if you click "close donate".. otherwise there's no way to close it.