Why coins (dataStorage) aren't saving when player leave the game?

i cant save the data when the player leave the game, but every time i try to save the player coins the function dont work :(

local DataStoreService = game:GetService("DataStoreService")

local dataCentral = {
    coins = 0,
}

local datas = {}
local canRun = false
function loadData(player)
    datas[player] = {}
    datas[player].coins = 0
    for i, v in pairs(dataCentral) do
        if not DataStoreService:GetDataStore(i):GetAsync(tostring(player.UserId)) then
            DataStoreService:GetDataStore(i):SetAsync(tostring(player.UserId), v)
        else
            dataCentral[i] = DataStoreService:GetDataStore(i):GetAsync(tostring(player.UserId))
            datas[player][i] = dataCentral[i]
            warn(DataStoreService:GetDataStore('coins'):GetAsync(tostring(player.UserId)))
        end
    end


    local stat = Instance.new("IntValue")
    stat.Name = "leaderstats"
    local cash = Instance.new("IntValue")
    cash.Name = "Coins"
    cash.Value = dataCentral.coins
    cash.Parent = stat
    stat.Parent = player

    if not canRun then
        canRun = true
        check()
    end
end 

function check()
    while true do
        for i, v in pairs(game.Players:GetChildren()) do
            if v.leaderstats.Coins.Value ~=  DataStoreService:GetDataStore('coins'):GetAsync(tostring(v.UserId)) then
                if v.leaderstats.Coins.Value ~= datas[v].coins then
                    datas[v].coins = v.leaderstats.Coins.Value
                end             
            end
        end
        wait()
    end
end

function saveData(player)
    DataStoreService:GetDataStore('coins'):SetAsync(tostring(player.UserId), datas[player].coins)

end

game:GetService("Players").PlayerAdded:connect(loadData)
game:GetService("Players").PlayerRemoving:connect(saveData)

The error is in the function saveData()