Dev product Owned?

When player buys this or already did buy it has to be come owned and then cannot buy it anymore, but its not working.. Its in a gui button. Can someone help me?

local productId = 25553578
local player = game.Players.LocalPlayer

script.Parent.MouseButton1Click:connect(function()
    Game:GetService("MarketplaceService"):PromptProductPurchase(player, productId)
end)

if player.productId then
    script.Parent.Text = "Owned"
else
    script.Parent.Text = "Double Tires (x10)"

end