NPC adds serial to item

[vitorelias1]

hi guys good nightI have this script but I don't know what's going on where I'm going wrongI will summarize the npc the player needs 1 crystal coin in exchange the npc adds a look to the item a serial.the script works removes the crystal coin but does not add the serial to the item
when the player looks at the item, it has to appear like this on the item

serialItem:setAttribute(ITEM_ATTRIBUTE_DESCRIPTION, "This item has been registered by the player " .. player:getName() .. " in day " .. os.date("%d/%m/%Y - %X") .. " Serial: " .. serial .. ".")

local keywordHandler = KeywordHandler:new()
local npcHandler = NpcHandler:new(keywordHandler)
NpcSystem.parseParameters(npcHandler)

local talkState = {}

function onCreatureAppear(cid)
    npcHandler:onCreatureAppear(cid)
end

function onCreatureDisappear(cid)
    npcHandler:onCreatureDisappear(cid)
end

function onCreatureSay(cid, type, msg)
    npcHandler:onCreatureSay(cid, type, msg)
end

function onThink()
    npcHandler:onThink()
end

function onCreatureSayCallback(cid, type, msg)
    if not npcHandler:isFocused(cid) then
        return false
    end

    local player = Player(cid) -- Get the Player Object

    if msgcontains(msg, "serial") then
        if player:getItemCount(2160) >= 1 then -- Check if the player has at least 1 Crystal Coin
            selfSay("I can provide a serial record for one of your items. In exchange, I need 1 Crystal Coin. Do you have an item you want to register?", cid)
            talkState[cid] = 1
        else
            selfSay("Sorry, but you need to have at least 1 Crystal Coin to use this service.", cid)
        end
    elseif talkState[cid] == 1 and (msgcontains(msg, "yes") or msgcontains(msg, "sim")) then
        local serialItem = player:getItemById(ITEMID_WILDCARD, true) -- Search for an item in the Backpack or Set
        if serialItem and serialItem:isItem() then
            if player:removeItem(2160, 1) then -- Remove 1 Crystal Coin from the player
                local serial = os.time() -- Generate time-based serial
                serialItem:setAttribute(ITEM_ATTRIBUTE_DESCRIPTION, "This item has been registered by the player " .. player:getName() .. " in day " .. os.date("%d/%m/%Y - %X") .. " Serial: " .. serial .. ".")
                selfSay("Your item has been successfully registered. He now has the following serial: " .. serial .. ".", cid)
            else
                selfSay("Sorry, there was an error removing the Crystal Coin. Please try again.", cid)
            end
        else
            selfSay("Sorry, but you don't have an item to register.", cid)
        end
        talkState[cid] = 0
    else
        selfSay("That's fine, come back when you're interested in registering an item.", cid)
        talkState[cid] = 0
    end

    return true
end

npcHandler:setCallback(CALLBACK_MESSAGE_DEFAULT, onCreatureSayCallback)
npcHandler:addModule(FocusModule:new())