I am making a chat GUI, but the scrollbar does not move enough. Any fixes?

I am making a chat GUI, but the scrollbar does not move enough. What it's designed to do is make the scrollingframe larger and scroll to the bottom when a new chat above line 22 (size) is present. It makes the scrollbar, but does not scroll down. Here's the code.

GUIData = {
	ChatBoxSize = UDim2.new(1, 0, 0, 20),
	ChatBoxStartPos = UDim2.new(0, 0, 1, -20),
	FontSize = "Size18",
	Color = Color3.new(1, 1, 1),
	StrokeColor = Color3.new(1, 1, 1),
	StrokeTrans = 1,
}


DesiredStyle = 2 --[[--Does 0 through 3, 4 styles--]]--

function HandleMessage(n, t, style)
	local text = nil
	if style == 0 then
		local text = n .. " : " .. t
		return text
	elseif style == 1 then
		local text = "["..n.."]: " .. t
		return text
	elseif style == 2 then
		local text = "<"..n..">: " .. t
		return text
	elseif style == 3 then
		local text = "("..n.."): " .. t
		return text
	end
end

CS = 0

function UpdateOldLabels(Parent, playerG)
	for i,v in pairs(Parent:GetChildren()) do
		if v.Name:sub(1,4):lower() == "line" then
			local LineNumber = v.Name:sub(5)
			local T = v.Name
			local LineNumberInt = tonumber(LineNumber)
			if LineNumberInt >= 22 then
				playerG.PlayerGui.ChatGUI.GUI.CanvasSize = playerG.PlayerGui.ChatGUI.GUI.CanvasSize + UDim2.new(0, 0, 0, A) --Add to the canvas size
				v.Name = "line"..tostring(tonumber(LineNumber) + 1)
				v.Position = v.Position - UDim2.new(0, 0, 0, A)
				if playerG.PlayerGui.ChatGUI.GUI.CanvasPosition.Y == CS then
					local A = 20
					CS = CS + A/2
					playerG.PlayerGui.ChatGUI.GUI.CanvasPosition = playerG.PlayerGui.ChatGUI.GUI.CanvasPosition + Vector2.new(0, CS) --Auto-scroll
				elseif playerG.PlayerGui.ChatGUI.GUI.CanvasPosition.Y < CS then --Catch if the player scrolled up to view previous chats. Prevent auto-scroll if they are
					playerG.PlayerGui.ChatGUI.GUI.CanvasPosition = playerG.PlayerGui.ChatGUI.GUI.CanvasPosition + Vector2.new(0, 0)
		   		end
			else
				v.Name = "line"..tostring(tonumber(LineNumber) + 1)
				v.Position = v.Position - UDim2.new(0, 0, 0, 20)
			end
		end
	end
end
 
game:GetService("Players").PlayerAdded:connect(function(player)
	player.Chatted:connect(function(msg)
		for _,v in ipairs(game:GetService("Players"):GetChildren()) do
			UpdateOldLabels(v:WaitForChild("PlayerGui").ChatGUI.GUI, player)
			newchatline = Instance.new("TextLabel",v:WaitForChild("PlayerGui").ChatGUI.GUI)
			newchatline.Text = HandleMessage(player.Name, msg, DesiredStyle)
			newchatline.Size = GUIData.ChatBoxSize
			newchatline.Position = GUIData.ChatBoxStartPos
			newchatline.Font = "SourceSans"
			newchatline.TextColor3 = GUIData.Color
			newchatline.TextStrokeTransparency = GUIData.StrokeTrans
			newchatline.BackgroundTransparency = 1
			newchatline.BorderSizePixel = 0
			newchatline.FontSize = GUIData.FontSize
			newchatline.TextXAlignment = "Left"
			newchatline.TextYAlignment = "Center"
			newchatline.ClipsDescendants = true
			newchatline.TextWrapped = true
			newchatline.Name = "line1"
		end
		UpdateOldLabels(game:GetService("StarterGui").ChatGUI.GUI, player)
		newchatline:Clone().Parent = game:GetService("StarterGui").ChatGUI.GUI
	end)
end)

U may be using the average Frame but wut u need to use is the ScrollBarFrame. Just go to advance objects and replace ur Frame with the ScrollBarFrame.