My DataSaving doesn't save any data?

I am currently trying to create a game, where if you win a round you earn 'Gems', but when you leave the game, they save for the next time you join the game. This is not what happens though, if you leave and rejoin, the gems are not saved, and I am unsure why, there is no error in the console when I test

Edit: I already have API Services turned on, and it still doesn't work.

local DSService = game:GetService('DataStoreService'):GetDataStore('Gems')
game.Players.PlayerAdded:Connect(function(plr)
	-- Defining variables
	local uniquekey = 'id-'..plr.userId
	local leaderstats = Instance.new('IntValue', plr)
	local savevalue =  Instance.new('IntValue')
	leaderstats.Name = 'leaderstats'	
	savevalue.Parent = leaderstats
	savevalue.Name = 'Gems'
	
	-- GetAsync
	local GetSaved = DSService:GetAsync(uniquekey)
	if GetSaved then
		savevalue.Value = GetSaved[1]
	else
		local NumbersForSaving = {savevalue.Value}
		DSService:SetAsync(uniquekey, NumbersForSaving)
	end
end)

game.Players.PlayerRemoving:Connect(function(plr)
	local uniquekey = 'id-'..plr.userId
	local Savetable = {plr.gems.Gems.Value}
	DSService:SetAsync(uniquekey, Savetable)	
end)