Lua Scripts disabling each other in Roblox Studio - lua

Question

I'm trying to make a game in Roblox (a tycoon) and, considering it's my first time making a game, I'm using some pre-made scripts and models along with youtube tutorials. My problem right now is that I have two scripts, both under the same name, DevProductHandler, (I've tried changing their names but the problem still persists) and it seems like only one will run at a time whenever I test the game. Disabling one script allows the other to run perfectly fine, and enabling both causes only one script to work, randomly picking which one will run each time.
One of the scripts is meant to control purchasing products that are prompted from a GUI, and the other controls purchases prompted from tycoon buttons that you walk on top of. I've tried merging the scripts by copy-pasting one underneath the other, but it still only makes the GUI DevProductHandler script work. I don't know if there are some overlapping variables or something that would cause one script to not allow the other to run, but I think that's most likely the issue, although I'm not sure how to go about fixing that I'm new at Lua and game creation so I was wondering if anyone could help me find out the issue. These are the scripts.
local Tycoon = script.Parent.Tycoons:GetChildren()[1]
script.Parent = game.ServerScriptService
local DevProducts = {}
local MarketplaceService = game:GetService('MarketplaceService')
for i,v in pairs(Tycoon:WaitForChild('Buttons'):GetChildren()) do
if v:FindFirstChild('DevProduct') then
if v.DevProduct.Value > 0 then
DevProducts[v.DevProduct.Value] = v -- the button
end
end
end
MarketplaceService.ProcessReceipt = function(receiptInfo)
for i,plr in pairs(game.Players:GetPlayers()) do
if plr.userId == receiptInfo.PlayerId then
if DevProducts[receiptInfo.ProductId] then
local obj = DevProducts[receiptInfo.ProductId]
local PlrT = game.ServerStorage.PlayerMoney:WaitForChild(plr.Name).OwnsTycoon
if PlrT.Value ~= nil then
--if PlrT.Value.PurchasedObjects:FindFirstChild(obj.Object.Value) == false then
local PlayerStats = game.ServerStorage.PlayerMoney:FindFirstChild(plr.Name)
Create({[1] = 0,[2] = obj,[3] = PlayerStats}, PlrT.Value.BuyObject)
--end
end
end
end
end
end
function Create(tab, prnt)
local x = Instance.new('Model')
Instance.new('NumberValue',x).Value = tab[1]
x.Value.Name = "Cost"
Instance.new('ObjectValue',x).Value = tab[2]
x.Value.Name = "Button"
local Obj = Instance.new('ObjectValue',x)
Obj.Name = "Stats"
Obj.Value = tab[3]
x.Parent = prnt
end
Above is the script for prompts from walking over buttons.
old_fog = game.Lighting.FogStart
local MarketplaceService = game:GetService("MarketplaceService")
function getPlayerFromId(id)
for i,v in pairs(game.Players:GetChildren()) do
if v.userId == id then
return v
end
end
return nil
end
MarketplaceService.ProcessReceipt = function(receiptInfo)
local productId = receiptInfo.ProductId
local playerId = receiptInfo.PlayerId
local player = getPlayerFromId(playerId)
local productName
if productId == 1172271849 then
local cashmoney = game.ServerStorage.PlayerMoney:FindFirstChild(player.Name)
if cashmoney then
cashmoney.Value = cashmoney.Value + 10000
end
elseif productId == 1172270951 then
local cashmoney = game.ServerStorage.PlayerMoney:FindFirstChild(player.Name)
if cashmoney then
cashmoney.Value = cashmoney.Value + 100000
end
elseif productId == 1172270763 then
local cashmoney = game.ServerStorage.PlayerMoney:FindFirstChild(player.Name)
if cashmoney then
cashmoney.Value = cashmoney.Value + 1000000
end
elseif productId == 1172272327 then
local cashmoney = game.ServerStorage.PlayerMoney:FindFirstChild(player.Name)
if cashmoney then
cashmoney.Value = cashmoney.Value + cashmoney.Value
end
elseif productId == 1172273117 then
local char = player.Character
if char then
local human = char:FindFirstChild("Humanoid")
if human then
human.WalkSpeed = human.WalkSpeed + human.WalkSpeed
end
end
elseif productId == 1172273437 then
game.ServerStorage.HyperlaserGun:Clone().Parent=player.Backpack
elseif productId == 1172272691 then
game.ServerStorage.FlyingCarpet:Clone().Parent=player.Backpack
end
return Enum.ProductPurchaseDecision.PurchaseGranted
end
Above is the script for purchases from a GUI prompt.

Answer 1

From the Roblox manual:
As with all callbacks, this function should be set once and only once
by a single Script. If you're selling multiple products in your game,
this callback must handle receipts for all of them.
You're implementing game:GetService('MarketplaceService').ProcessReceipt in both scripts. One overwrite the other.