My notification system is having issues with the error "attempt to call instance value"

So the full code is here in the two parts: Server and Local. I am trying to make a system that stores the Balance of the user, from the table, in a IntValue inside of their player in game.Players then call it later to check if it has changed. If It has, send a Notification to the GUI via a local script. Whatever happens, the notification does not appear. If you need anything else, I'm happy to give you it. Thanks for reading and any potential help. This is for a game called Opix Islands on Roblox, I am not an expert nor a noob, I just got a bit stuck.

Server:

    while true do
    for i,v in game.Players do --this is the line with the error.

            local tab = nil
            for I,V in pairs(_G.GlobalData) do
                if V.UserId == v.UserId then
                    tab = V
                end
            end
            if not v.Bank then
                newval = Instance.new("IntValue",v)
                newval.Name = "Bank"
                wait()
                newval.Value = tab.Bank

            else
                if tab.Bank > v.Bank.Value then
                    print ("Greater than stored value")
                    local changedby = tab.Bank - v.Bank.Value
                    game.ReplicatedStorage.Notif.Return:FireClient(v,changedby,false)
                elseif tab.Bank < v.Bank.Value then
                    print ("Less than stored value")
                    local changedby = v.Bank.Value - tab.Bank
                    game.ReplicatedStorage.Notif.Return:FireClient(v,changedby,true)--Player to send to,amount it has changed by,If it has gone down
                end             
            end
            
        end

    wait()  
    end
    

And the Local script:

game.ReplicatedStorage.Notif.Return.OnClientEvent:Connect(function(Change,Down)
     if Down == false then
        local Notification = script.Parent.NotificationExample:Clone()
        Notification.Name = "Notification"
        Notification.Parent = script.Parent
        Notification.Text = "Your Bank account balance has just increased by: £"..Change
        print ("Bank account Increased by:"..Change)
        Notification.Visible = true
        print ("Notification should be visible")
        wait(3)
        Notification:Destroy()
        print ("Notification should be gone!")
    elseif Down == true then
            local Notification = script.Parent.NotificationExample:Clone()
            Notification.Parent = script.Parent
            Notification.Name = "Notification"
            Notification.Text = "Your Bank account balance has just decreased by: £"..Change
            print ("Bank account decreased by:"..Change)
            Notification.Visible = true
            print ("Notification should be visible")
            wait(3)
            Notification:Destroy()
            print ("Notification should be gone!")
    
    
    
    end
    
    
end)

Here's a picture of the hierarchy, the event is in the replicated storage.

Many Thanks.