Help with Admin Command to Change Leaderstat Value?

I am trying to make a command that the people listed as Admin below can run to change a certain player's stage number. When I use the script, instead of setting the player's stage to the number, it resets it to zero and gives no errors for me to go off of. I'm new to scripting, so any help would be appreciated.

local Admins = {
	90188191;
	87578761;
	269848417;
}
local Prefix = ";"

local Players = game:GetService("Players")

local Commands = {}

Commands.set = function(Sender, Arguments)
	local Username = Arguments[1]
	table.remove(Arguments,1)
	local Number = Arguments[2]
	local Stage = game.Players[Username].leaderstats.Stage
	Stage.Value = Number
end

local function IsAdmin(Player)
	for _,Admin in pairs (Admins) do
		if type(Admin) == "string" and string.lower(Admin) == string.lower(Player.Name) then
			return true
		elseif type(Admin) == "number" and Admin == Player.UserId then
			return true
		end
	end
	return false
end

local function ParseMessage(Player,Message)
	local PrefixMatch = string.match(Message,"^"..Prefix)
	
	if PrefixMatch then
		Message = string.gsub(Message,PrefixMatch,"",1)
		local Arguments = {}
		
		for Argument in string.gmatch(Message,"[^%s]+") do
			table.insert(Arguments,Argument)
		end
		
		local CommandName = Arguments[1]
		table.remove(Arguments,1)
		local CommandFunc = Commands[CommandName]
		
		if CommandFunc ~= nil then
			CommandFunc(Player,Arguments)
		end
	end
end

Players.PlayerAdded:Connect(function(Player)
	Player.Chatted:Connect(function(Message,Recipient)
		if not Recipient and IsAdmin(Player) then
			ParseMessage(Player,Message)
		end
	end)
end)