£1000 Lost inventory

Hi.

I have around £1000 worth of stock which was checked into Amazon warehouses which was not added to my inventory. This was months ago and all shows as received in the shipment reports. Have been trying to get help from support but they are useless. Just saying it’s not eligible for investigation. I’ve been going back and forth with them for over a week now. Can anyone support me with a contact. I hear people get in touch with the managing director but I do not have the email.