Since you do not know which editor has been assigned to you, there is no way you can contact the editor directly. Under the circumstances, I think it would be best to wait for a couple of weeks more and then write to the journal once again. You should explain that you had written earlier and were told that they would contact the editor and get back to you, but have not yet responded. You could also politely request them to expedite the process. Keep sending reminders every couple of weeks till they respond. If you do not receive a response even after sending multiple reminders, you can consider withdrawing your paper.