How do I prevent Guis from cloning the same Gui twice?

So uh I have an inventory script and a backpack gui. Everything functions however in this link you will see a weird bug where all the items cloned twice. Does anyone know how to delete extra clones?

https://gyazo.com/22c8c5ba3b43124ef87678666f3f45cf

this is the backpack script:

local player = game.Players.LocalPlayer
local character = player.Character
local items = {}
local buttons = {}
game.StarterGui:SetCoreGuiEnabled(Enum.CoreGuiType.Backpack,false) -- Makes the original backpack gui invisible

function search()
    for i,v in pairs(game.Players.LocalPlayer.Backpack:GetChildren()) do -- Find all item in a specific location
        if v:isA("Tool") then -- If the item found is a "Tool"
            table.insert(items,v) -- We're going to put all the tools found in a table.
        end
    end
end

function refresh()
    for i,v in pairs(buttons) do -- Finds all items in the table
        v:Destroy() -- Destroy 'em all
    end
    for i,v in pairs(items) do -- Finds all items in the table
        local button = script.Sample:Clone() -- clones the sample button inside the localscript
        button.Name = v.Name -- sets the cloned button's name to the name of the item
        button.LayoutOrder = i
        button.Parent = script.Parent.Handler -- Sets the parent of the cloned button to the handler
        button.Image = v.TextureId -- Sets the image of the button to the texture id of the tool
        button.ZIndex = 7
        button.BackgroundColor3 = Color3.fromRGB(50,50,50)
        button.BorderColor3 = Color3.fromRGB(25,25,25)
        button.BorderMode = Enum.BorderMode.Inset
        button.BorderSizePixel = 5
        table.insert(buttons,button) -- Inserts the button to our table "buttons"
        button.MouseButton1Click:connect(function()
            if script.Parent.Handler.Selected.Value == nil or script.Parent.Handler.Selected.Value ~= v then -- Checks if the selected value is nothing or if the selected value is not the button
                script.Parent.Frame.ItemName.Text = v.Name -- Sets the TextLabel's Text to the name of the tool/button
                script.Parent.Frame.ImageLabel.Image = v.TextureId -- Sets the image label's image to the texture id of the tool
                script.Parent.Handler.Selected.Value = v
                if script.Parent.Handler.Selected.Value ~= script.Parent.Handler.Equipped.Value then --if the selected value is not the same as the equipped value then
                    script.Parent.Handler.Location.Value = v.Parent -- Sets the value of our location to the parent of the tool whether it is in the backpack or in the character
                    script.Parent.Frame.Equip.Text = "Equip" -- Self explanatory
                elseif script.Parent.Handler.Selected.Value == script.Parent.Handler.Equipped.Value then -- If the selected value is the same as the equipped value then...
                    script.Parent.Handler.Location.Value = v.Parent
                    script.Parent.Frame.Equip.Text = "Unequip"
                end
            end
        end)
    end
end

function backpackRefresh()
    items = {}
    search(character)
    search(player.Backpack)
    refresh()
end

backpackRefresh()

player.Backpack.ChildAdded:connect(backpackRefresh)
player.Backpack.ChildRemoved:connect(backpackRefresh)

character.ChildAdded:connect(backpackRefresh)
character.ChildRemoved:connect(backpackRefresh)