I wanted to activate a custom destruction effect for a monster by returning a pendulum monster from my extra deck to my main deck as a cost, but it won't activate. What is wrong in the script? This is what it currently looks like:

--destroy
local e1=Effect.CreateEffect(c)
e1:SetCategory(CATEGORY_DESTROY)
e1:SetType(EFFECT_TYPE_IGNITION)
e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
e1:SetRange(LOCATION_MZONE)
e1:SetCost(c15925308.descost)
e1:SetTarget(c15925308.destg)
e1:SetOperation(c15925308.desop)
c:RegisterEffect(e1)
end
function c15925308.costfilter(c)
return c:IsFaceup() and c:IsType(TYPE_PENDULUM) and c:IsSetCard(xxxx) and c:IsAbleToDeckAsCost()
end
function c15925308.descost(e,tp,eg,ep,ev,re,r,rp,chk)
if chk==0 then return Duel.IsExistingMatchingCard(c15925308.costfilter,tp,LOCATION_EXTRA,0,1,nil) end
Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_TODECK)
local g=Duel.SelectMatchingCard(tp,c15925308.costfilter,tp,LOCATION_EXTRA,0,1,1,nil)
Duel.SendtoDeck(g,nil,2,REASON_COST)
end
function c15925308.destg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
if chkc then return chkc:IsControler(1-tp) and chkc:IsOnField() end
if chk==0 then return Duel.IsExistingTarget(aux.TRUE,tp,0,LOCATION_ONFIELD,1,nil) end
Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_DESTROY)
local g=Duel.SelectTarget(tp,aux.TRUE,tp,0,LOCATION_ONFIELD,1,1,nil)
Duel.SetOperationInfo(0,CATEGORY_DESTROY,g,1,0,0)
end
function c15925308.desop(e,tp,eg,ep,ev,re,r,rp)
local tc=Duel.GetFirstTarget()
if tc and tc:IsRelateToEffect(e) then
Duel.Destroy(tc,REASON_EFFECT)
end
end

	local s,id=GetID()
	function s.initial_effect(c)
	--destroy
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_DESTROY)
	e1:SetType(EFFECT_TYPE_IGNITION)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetRange(LOCATION_MZONE)
	e1:SetCost(s.descost)
	e1:SetTarget(s.destg)
	e1:SetOperation(s.desop)
	c:RegisterEffect(e1)
end
function s.cfilter(c)
	return c:IsFaceup() and c:IsType(TYPE_PENDULUM) and c:IsAbleToDeckAsCost()
end
function s.descost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.cfilter,tp,LOCATION_EXTRA,0,1,nil) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_RTODECK)
	local g=Duel.SelectMatchingCard(tp,s.cfilter,tp,LOCATION_EXTRA,0,1,1,nil)
	Duel.SendtoDeck(g,nil,1,REASON_EFFECT)
end
function s.destg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsOnField() and chkc~=e:GetHandler() end
	if chk==0 then return Duel.IsExistingTarget(aux.TRUE,tp,LOCATION_ONFIELD,LOCATION_ONFIELD,1,e:GetHandler()) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_DESTROY)
	local g=Duel.SelectTarget(tp,aux.TRUE,tp,LOCATION_ONFIELD,LOCATION_ONFIELD,1,1,e:GetHandler())
	Duel.SetOperationInfo(0,CATEGORY_DESTROY,g,1,0,0)
end
function s.desop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc:IsRelateToEffect(e) then
		Duel.Destroy(tc,REASON_EFFECT)
	end
end