why does my scripts do not communicate? (or im just dumb)

so check this, i think i did code right but it's not working so can ya help?

function handleKillCount(humanoid, player)
	local killer = getKillerOfHumanoidIfStillInGame(humanoid)
	if killer ~= nil then
		local stats = killer:findFirstChild("leaderstats")
		if stats ~= nil then
			local kills = stats:findFirstChild("Kills")
			local spree = stats:findFirstChild("Kill Streak")
			if killer ~= player then
				kills.Value = kills.Value + 1
				spree.Value = spree.Value + 1
			else
				kills.Value = kills.Value - 1

			end
		end
	end
end

this is the part of free model that does work

local phase0 = true
local phase1 = false
if game.Workspace.MainLeaderstats.spree.Value < 1 then phase0 = false and phase1 == true
if phase1 == true then game.StarterPack.Hammer.Handle.phase1par.Enabled = true end end

this is da code by me in the serverscriptservice

and "phase1par" (particle) is in da hammer (tool in starterpack) thanks