After a couple of tries this allows me to use the same code multiple times?

local Data = game:GetService("DataStoreService"):GetDataStore("Codes")

local On = game.ReplicatedStorage.Remotes.Codes

function Reward(plr,code)
    local SavedStuff = Data:GetAsync(plr.userId)
    if SavedStuff ~= nil then
        for i,v in pairs(SavedStuff)do
            if v == code then
                return "Already Redeemed!"
            else
                if game.ServerStorage.Codes:FindFirstChild(code) ~= nil then
                    local RealCode = game.ServerStorage.Codes:FindFirstChild(code)
                    if RealCode.Value == "RewardPoints" then
                        local Points = plr.leaderstats.EmPoints
                        local SaveCode = {}
                        table.insert(SaveCode,code)
                        Data:SetAsync(plr.userId,SaveCode)
                        Points.Value = Points.Value + 150
                        return "Redeemed!"
                    end
                else
                    return "Invalid or Expired Code!"
                end
            end
        end
    else
        if game.ServerStorage.Codes:FindFirstChild(code) ~= nil then
            local RealCode = game.ServerStorage.Codes:FindFirstChild(code)
            if RealCode.Value == "RewardPoints" then
            local Points = plr.leaderstats.EmPoints
            local SaveCode = {}
            table.insert(SaveCode,code)
            Data:SetAsync(plr.userId,SaveCode)
            Points.Value = Points.Value + 150
            return "Redeemed!"
        end
        else
            return "Invalid or Expired Code!"
        end
    end
end

On.OnServerInvoke = Reward

For whatever reason, this script is supposed to save the code that the player used and when I use the code after like 2 seconds it allows me to use it once again, I have no clue what is happening here.