Dev Product Reciept Not Working? [closed]

I put a regular script into the Starterpack. (Unsure if this is the problem.) I'm trying to send leaderstats NumberValue "Coins". Purchasing works, but sending the "Coins" won't. Any help on how to fix this?

local MarketplaceService = Game:GetService("MarketplaceService")
local ds = game:GetService("DataStoreService"):GetDataStore("PurchaseHistory")

MarketplaceService.ProcessReceipt = function(receiptInfo)
    print("Testing Receipt Loaded")
    local playerProductKey = "player_" .. receiptInfo.PlayerId .. "_product_" .. receiptInfo.ProductId
    local numberBought = ds:IncrementAsync(playerProductKey, 1)
    for i,v in pairs (game.Players:GetChildren()) do
        if v.userId == receiptInfo.PlayerId then
            if receiptInfo.ProductId == 19918045 then
                print("Did this succeed?")


                lds = v:FindFirstChild("leaderstats")
                if lds ~= nil then
                    cs = lds:FindFirstChild("Coins") 
                    if cs ~= nil then
                        cs.Value = cs.Value + 100
                        print("Coins Sent") 
                    end
                end
            end
        end
    end
    return Enum.ProductPurchaseDecision.PurchaseGranted     
end