Lost or Missing items on FBA warehouse in Moreno Valley, CA ONT8


whenever I send my inventory to Moreno Valley, CA ONT8 warehouse my items getting lost.
here how they work, first they receive them partially until it show in the system that the full qty of what you send and after a week they start to move some to other facilities. on this procedure if you have high end and good items some will be disappears and your inventory will be adjusted by insiders and you cannot get back anything or prove. I complained to seller support they are not really helping they are more like machine in human body. after complain they are telling me that you did not send the qty that you supposed to send. bacillary there is a team inside that they are doing this professionally for many years.
is anyone knows how to deal with this kind of cases? is there any management email or higher level of support contact?