[SOLVED] Unable to cast Instance to int64?

Explanation: So I was trying to make a top donator leaderboard. However, I ended up encountering an error while trying to do so. I was trying to save the info of the donation that a player made into a DataStore so that the leaderboard updates. But when I put the second argument which was supposed to be the value of the DataStore in line 43, it gives me an error saying "Unable to cast Instance to int64". This may be because I got no clue how to write the second argument and so I tried to get the PriceInRobux and make it as a value for the argument by doing:

game:GetService("MarketplaceService"):GetProductInfo(--[[Some Arguments here]]).PriceInRobux

I know I was not supposed to do that. Does anyone have any idea how to write the second argument?

Here's the ServerScript named "DeveloperProductServer" located in ServerScriptService:

local MarketPlaceService = game:GetService("MarketplaceService")
local DataStoreService = game:GetService("DataStoreService")
local RobuxDataStore = DataStoreService:GetOrderedDataStore("RobuxDateStore")
local RobuxDonateEvent = game:GetService("ReplicatedStorage"):WaitForChild("EventsFolder"):WaitForChild("RobuxDonateEvent")

local function UpdateLeaderBoard()
	local Success, ErrorMessage = pcall(function()
		local Data = RobuxDataStore:GetSortedAsync(false, 15)
		local RobuxDSPage = Data:GetCurrentPage()
		for RobuxDonated, data in ipairs(RobuxDSPage) do
			local Username = game:GetService("Players"):GetNameFromUserIdAsync(tonumber(data.key))
			local RobuxAmount = data.value
			local IsOnLeaderBoard = false
			for i, v in pairs(workspace:WaitForChild("GlobalLeaderboard"):WaitForChild("lbGUI"):WaitForChild("Holder"):GetChildren()) do
				if v.Player.Text == Username then
					IsOnLeaderBoard = true
					break	
				end
			end
			if RobuxAmount and IsOnLeaderBoard == false then
				local ClonelbFrame = game:GetService("ServerStorage"):WaitForChild("lbFrame"):Clone()
				ClonelbFrame.Player.Text = Username
				ClonelbFrame.Amount.Text = RobuxAmount
				ClonelbFrame.Position = UDim2.new(0, 0, ClonelbFrame.Position.Y.Scale + (0.08 * #workspace:WaitForChild("GlobalLeaderboard"):WaitForChild("lbGUI"):WaitForChild("Holder"):GetChildren()), 0)
				ClonelbFrame.Parent = workspace:WaitForChild("GlobalLeaderboard"):WaitForChild("lbGUI"):WaitForChild("Holder")
			end
		end
	end)
	if not Success then
		error(ErrorMessage)
	end
end
 
local function processReceipt(ReceiptInfo)
	local PlayerUserId = game:GetService("Players"):GetPlayerByUserId(ReceiptInfo.PlayerId)
	if not PlayerUserId then
		return Enum.ProductPurchaseDecision.NotProcessedYet
	end
	print("Player Donated Robux!")
	RobuxDonateEvent:FireClient(PlayerUserId)
	while true do
		for _, Player in pairs(game:GetService("Players"):GetPlayers()) do
			RobuxDataStore:SetAsync(game:GetService("Players"):GetNameFromUserIdAsync(PlayerUserId)) -- What Do I Write For The Second Argument??
		end
		for _, Frame in pairs(workspace:WaitForChild("GlobalLeaderboard"):WaitForChild("lbGUI"):WaitForChild("Holder"):GetChildren()) do
			Frame:Destroy()
		end
		UpdateLeaderBoard()
		wait(10)
	end
	return Enum.ProductPurchaseDecision.PurchaseGranted
end

MarketPlaceService.ProcessReceipt = processReceipt