How to resize accessory upwards only?

So I have a backpack and each time a player picks an item up the backpack get bigger upwards, the thing is it get bigger upwards and downwards, I guess because of the attachment of the accessory???

Here's the script for the backpack to get bigger

script.Parent.Touched:Connect(function(hit)
	if hit and hit.Parent and game.Players:GetPlayerFromCharacter(hit.Parent) then
		local Team = game:GetService("Teams")
		local ReplicatedStorage = game:GetService("ReplicatedStorage")
		local Resize = require(ReplicatedStorage.Resize)
		local PINK = Team.Pink
		local pinkblock = hit.Parent.PINKBLOCK
		local player = game.Players:GetPlayerFromCharacter(hit.Parent)
		if player.Team == PINK  then
			script.Parent["Click Sound"]:Play()
			print("resized")
			Resize(pinkblock.Handle, Enum.NormalId.Top, 2.239)
			script.Parent:Destroy()
		else
			print("didnt resize")
		end
	end
end)

Here's the module:

local NORMAL_DIRECTIONS = {
	[Enum.NormalId.Top] = Vector3.new(0, 1, 0);
	[Enum.NormalId.Bottom] = Vector3.new(0, -1, 0);
	[Enum.NormalId.Back] = Vector3.new(0, 0, 1);
	[Enum.NormalId.Front] = Vector3.new(0, 0, -1);
	[Enum.NormalId.Right] = Vector3.new(1, 0, 0);
	[Enum.NormalId.Left] = Vector3.new(-1, 0, 0);
}

return function(part, normal, delta)
	local Direction = NORMAL_DIRECTIONS[normal]
	part.Size = part.Size + Vector3.new(math.abs(Direction.X), math.abs(Direction.Y), math.abs(Direction.Z))*delta
	part.CFrame = part.CFrame + NORMAL_DIRECTIONS[normal]*delta/2
end

Can anyone help me?

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