MarketPlaceService + Data Store script not functioning 100%

In the startpack I have a localscript with this:

local productId = 19186931
plr = game.Players.LocalPlayer
plrgui = plr:WaitForChild("PlayerGui")

plrgui.ChildAdded:connect(function(child)
if child.Name == "EndGui" then
    wait()
    buyButton = script.Parent.Parent.PlayerGui.EndGui.Continue
    buyButton.MouseButton1Click:connect(function()
    if buyButton.Visible == true then
    Game:GetService("MarketplaceService"):PromptProductPurchase(game.Players.LocalPlayer, productId)
    end
end)
    end
end)

This script seemingly works perfectly. It fires the transaction, so that's all good! It's the server side script in Workspace that seems to have problems.

This is the server script:

local MarketplaceService = Game:GetService("MarketplaceService")
local productId = 19186931
local ds = game:GetService("DataStoreService"):GetDataStore("ContinueButton")

function GetPlayerById(id)
    for _,v in ipairs(game.Players:GetPlayers())do
        if(v.userId==id)then
        return(v) 
        end
    end
    return(nil)
end

MarketplaceService.ProcessReceipt = function(receiptInfo)
    if receiptInfo.ProductId == productId then
    local asynccode = receiptInfo.PlayerId .. "buys"
        if ds:GetAsync(asynccode) == nil then
            ds:SetAsync(asynccode, 0) 
        end
    ds:IncrementAsync(asynccode, 1)
    print("Player bought the continue developer product. Player now has "..ds:GetAsync(asynccode).." buys.")

    currentplr = GetPlayerById(receiptInfo.PlayerId)

    gui = currentplr.PlayerGui
    gui.continuegame.Disabled = false

    return Enum.ProductPurchaseDecision.PurchaseGranted     
    end
    end

I have tried using both ROBLOX remote error and Obox checking system but neither print any of the prints I have and neither display any errors.. But it doesn't work!

What's wrong? If you can offer a solution to the debugger that'd be even better!