diff --git a/cmd/hubserver/storage/postgres.go b/cmd/hubserver/storage/postgres.go
index 689e57c..d4cc997 100644
--- a/cmd/hubserver/storage/postgres.go
+++ b/cmd/hubserver/storage/postgres.go
@@ -36,7 +36,7 @@ func (s *postgres) Subscribe(topic string, sub Subscriber) error {
 
 func (s *postgres) Unsubscribe(topic, callback string) error {
 	_, err := s.db.Exec(
-		`DELETE FROM "subscribers" WHERE "topic" = ? AND "callback" = $1`,
+		`DELETE FROM "subscribers" WHERE "topic" = $1 AND "callback" = $2`,
 		topic,
 		callback,
 	)