diff --git a/bot/command_owner.go b/bot/command_owner.go
index becd5fe..962b8a8 100644
--- a/bot/command_owner.go
+++ b/bot/command_owner.go
@@ -98,9 +98,5 @@ func (b *Bot) setOption(ctx context.Context, name, value string) {
 		return
 	}
 
-	if name == roomOptionMailbox {
-		value = value + "@" + b.domain
-	}
-
 	b.SendNotice(ctx, evt.RoomID, fmt.Sprintf("`%s` of this room set to `%s`", name, value))
 }
diff --git a/utils/utils.go b/utils/utils.go
index ddc1b28..93271da 100644
--- a/utils/utils.go
+++ b/utils/utils.go
@@ -11,7 +11,7 @@ func Mailbox(email string) string {
 	if index == -1 {
 		return email
 	}
-	return email[:strings.LastIndex(email, "@")]
+	return email[:index]
 }
 
 // Hostname returns hostname part from email address