diff --git a/core/service.go b/core/service.go
index f15f454..2c4387a 100644
--- a/core/service.go
+++ b/core/service.go
@@ -1,7 +1,6 @@
 package core
 
 import (
-	"context"
 	"encoding/hex"
 	"encoding/json"
 	"errors"
@@ -434,6 +433,7 @@ func (sh *serviceDescription) unlink(w http.ResponseWriter, r *http.Request) {
 	sType := queryvals.Get("stype")
 	sId := queryvals.Get("sid")
 	sk := queryvals.Get("sk")
+	targetType := queryvals.Get("ttype")
 
 	authInfo := sh.auths.Find(sk)
 	if authInfo == nil {
@@ -457,38 +457,39 @@ func (sh *serviceDescription) unlink(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	numRecord, err := sh.mongoClient.Collection(CollectionAccount).CountDocuments(context.Background(), bson.M{
+	accDocs, err := sh.mongoClient.FindAll(CollectionAccount, bson.M{
 		"accid": authInfo.Accid,
-	}, options.Count().SetLimit(2))
+	}, options.Find().SetProjection(bson.M{
+		"_id": 1,
+	}))
 
 	if err != nil {
 		logger.Error("unlink failed, fail to count accounts :", err)
 		w.WriteHeader(http.StatusBadRequest)
 	}
 
-	if numRecord <= 1 {
+	if len(accDocs) <= 1 {
 		logger.Println("unlink failed. At least one link must be maintained. :", r.URL.Query())
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 
-	sType, sId, err = sh.getProviderInfo(sType, sId)
-	if err != nil {
-		logger.Error("getProviderInfo failed :", err)
-		w.WriteHeader(http.StatusBadRequest)
+	var ids primitive.A
+	for _, accDoc := range accDocs {
+		ids = append(ids, accDoc["_id"].(primitive.ObjectID))
 	}
 
 	link, err := sh.mongoClient.FindOneAndDelete(CollectionLink, bson.M{
-		"platform": sType,
-		"uid":      sId,
+		"platform": targetType,
+		"_id":      bson.M{"$in": ids},
 	}, options.FindOneAndDelete().SetProjection(bson.M{"_id": 1}))
 	if err != nil {
-		logger.Error("link failed. FindOneAndDelete link err:", err)
+		logger.Error("unlink failed. FindOneAndDelete link err:", err)
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
 
-	newid, err := sh.mongoClient.FindOneAndDelete(CollectionAccount, bson.M{
+	preid, err := sh.mongoClient.FindOneAndDelete(CollectionAccount, bson.M{
 		"_id": link["_id"].(primitive.ObjectID),
 	}, options.FindOneAndDelete().SetProjection(bson.M{"_id": 1}))
 	if err != nil {
@@ -496,10 +497,7 @@ func (sh *serviceDescription) unlink(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
-
-	// newid가 있어야 한다. 그래야 기존 서비스 계정이 없는 상태이다.
-	if newid == nil {
-		// 이미 계정이 있네?
+	if preid == nil {
 		logger.Println("unlink failed. service account not found:", r.URL.Query())
 		w.WriteHeader(http.StatusBadRequest)
 		return