Script cant find something in PlayerGui even though I know it is there, why?

elseif receiptInfo.ProductId == GoldID then
        player.PlayerGui.Money.backdrop.money.Value = player.PlayerGui.Money.backdrop.money.Value + 1000
    end

this is a snippet of the code used and it works in roblox studio test mode and it cant find the gui "Money" in PlayerGui this is really weird as I KNOW that the gui is in StarterGui and PlayerGui (when the game starts) so I just really dont understand why it cant find it.

Do I need to do this through a RemoteEvent or a RemoteFunction seen as the game is Filtering Enabled?