Mouse is not getting locked with UserInputService

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1

I must make a mouse unlocker when a phone is opened.i used userinputservice for that but the mouse is still not getting unlocked.if i dont do it,then pc players will not able to control phone.

i tried enable modal in phone but they seems do not work.

script

local UIS = game:GetService("UserInputService")
local Plr = game:GetService("Players").LocalPlayer
local NotificationService = require(game:GetService("ReplicatedStorage").Services.Notification)

if UIS.TouchEnabled == true then
	Plr:WaitForChild("PlayerGui").MobileButtons.Enabled = true
end

-- Disable --
game:GetService("StarterGui"):SetCoreGuiEnabled(Enum.CoreGuiType.PlayerList,false)


-- Functions --
local function Phone()
	script.Click:Play()
	local UI = Plr.PlayerGui:WaitForChild("Phone")
	if UI.PhoneFrame.Screen.Values.IsUsing.Value == true then
		game:GetService("ReplicatedStorage").Phone:FireServer("R")
		UI.PhoneFrame.Screen.Values.IsUsing.Value = false
		UIS.MouseBehavior = Enum.MouseBehavior.LockCenter
		game:GetService("TweenService"):Create(UI.PhoneFrame,TweenInfo.new(0.25,Enum.EasingStyle.Quad),{Position = UDim2.new(0.745,0,1.2,0)}):Play()
		task.wait(0.25)
		game:GetService("StarterGui"):SetCoreGuiEnabled(Enum.CoreGuiType.Backpack,true)
	else
		game:GetService("ReplicatedStorage").Phone:FireServer("A")
		game:GetService("StarterGui"):SetCoreGuiEnabled(Enum.CoreGuiType.Backpack,false)
		UIS.MouseBehavior = Enum.MouseBehavior.Default
		UI.PhoneFrame.Screen.Values.IsUsing.Value = true
		game:GetService("TweenService"):Create(UI.PhoneFrame,TweenInfo.new(0.25,Enum.EasingStyle.Quad),{Position = UDim2.new(0.745,0,0.452,0)}):Play()
	end
end


-- Events --
UIS.InputBegan:Connect(function(input,gp)
	if gp then
		return
	end
	if input.KeyCode == Enum.KeyCode.Tab then
		Phone()
	end
end)
2

UIS.MouseBehaviour = Enum.MouseBehaviour.LockCenter, has to be ran either under RunService.Heartbeat or RunService.RenderStepped, all depends on what you want to use.