Why wont the billboard gui change color?

Here's my script (Local Script)

script.Parent.Size = 50
script.Parent.Parent.ClickDetector.MouseClick(function()
	script.Parent.cooldown.front.BackgroundColor3 = Color3.new(1, 0.4, 0.4)
end)

the background color of a imagelabel under a billboard GUI is supposed to change colors when the block it is inside of is clicked, however, it wont. I have been at this for hours trying to fix it and i've finally given up. Any ideas why it wont work? Any help is greatly appreciated.

That's not how you connect to an event... It would look something like this:

script.Parent.Parent.ClickDetector.MouseClick:Connect(function()
	-- code
end)

It may also help if you checked on the documentation for events.