[SOLVED] Leaderstats value not decreasing?

I am currently working on a shop system and I came accross this issue. Here's my script.

local CoolDown = true
script.Parent.Touched:Connect(function(hit)
	if hit.Parent:WaitForChild('Humanoid') then
		local player = game.Players:GetPlayerFromCharacter(hit.Parent)
		local PlayerGui = player.PlayerGui
		if CoolDown == true then
			CoolDown = false
			PlayerGui.ShopGui.TextLabel:TweenPosition(UDim2.new(0.5,0,0.5,0),'Out','Sine',.5)
			PlayerGui.ShopGui.TextLabel.Text = "Are you sure you want to purchase this item for $"..script.Parent.Price.Value.."?"
			wait(2)
			CoolDown = true
			PlayerGui.ShopGui.TextLabel.Yes.MouseButton1Click:Connect(function()
				if player.leaderstats.Yen.Value > 150 then
					PlayerGui.ShopGui.TextLabel:TweenPosition(UDim2.new(0.5,0,1.5,0),'In','Sine',.5)
					player.leaderstats.Yen.Value = player.leaderstats.Yen.Value - script.Parent.Price.Value
				end
			end)
			PlayerGui.ShopGui.TextLabel.No.MouseButton1Click:Connect(function()
				PlayerGui.ShopGui.TextLabel:TweenPosition(UDim2.new(0.5,0,1.5,0),'In','Sine',.5)
			end)
		end
	end
end)

Everything is supposed to work, but it's not. The items are not being purchased. Any help?

When ankurbohra04 said his answer, I tried it and it didn't work. Any perhaps I did something wrong? This is my updated scripts.

Server side script:

game.Players.PlayerAdded:Connect(function(plr)
	local CoolDown = true
	print(plr:WaitForChild('leaderstats'):WaitForChild('Yen').Value)
	script.Parent.Touched:Connect(function(hit)
		if hit.Parent:WaitForChild('Humanoid') then
			local player = game.Players:GetPlayerFromCharacter(hit.Parent)
			local PlayerGui = player.PlayerGui
			if CoolDown == true then
				CoolDown = false
				game.ReplicatedStorage.ConfirmPurchase:FireClient(player)
				wait(2)
				CoolDown = true
				PlayerGui.ShopGui.TextLabel.Yes.MouseButton1Click:Connect(function()
					if player:WaitForChild('leaderstats'):WaitForChild('Yen').Value >= 150 then
						game.ReplicatedStorage.CloseGui:FireClient(player)
						plr:WaitForChild('leaderstats'):WaitForChild('Yen').Value = plr:WaitForChild('leaderstats'):WaitForChild('Yen').Value - 150
					end
				end)
				PlayerGui.ShopGui.TextLabel.No.MouseButton1Click:Connect(function()
					game.ReplicatedStorage.CloseGui:FireClient(player)
				end)
			end
		end
	end)
end)

Here's my localscript:

game.ReplicatedStorage.ConfirmPurchase.OnClientEvent:Connect(function()
	script.Parent:TweenPosition(UDim2.new(0.5,0,0.5,0),'Out','Sine',.5)
	script.Parent.Text = "Are you sure you want to purchase this item for $"..workspace.CommonEgg.Price.Value.."?"
end)
game.ReplicatedStorage.CloseGui.OnClientEvent:Connect(function()
	script.Parent:TweenPosition(UDim2.new(0.5,0,1.5,0),'Out','Sine',.5)
end)

Can someone else help please?

EDIT: It worked! Thank you so much! It turns out that it only worked in-game, not in studio test mode. Once again, I cannot thank you enough for this, ankurbo04!