California landlord not providing locked mailboxes ..stolen mail

[Pamela Smith]

Hi I am a California  tenant  living in a rental community of 35 homes.

Our mail is delivered to the managers office where it is put into one locked mailbox.  . The manager then gets the mail and sorts it into our individual cubby that don't have a door so obviously it is not locked.

I also have 2 rental properties with the rent is sent to me at this address. Recently the manager has avoided me and locking the office door so I am unable to get my mail. Asking for my mail I have been told through the locked door that I do not have any mail. My tenants are regular with their rent always paying me by the 5th or 6th of each month with a money order. So I know when I will most likely have their mail. Then the manager started handing me my mail at the door. But it was now at the end of the month and both rental checks had not been received. 

I then communicated with both of my tena ts and each stated that they sent the rent and will send me a copy of the receipt. When I received the copies I called on the money orders and they had both been cashed  on the same day and time .so now I had to request a copy from the issuing  money order. I received the copies and on the front somebody added after my name " and/or " and then someone's name I dont know but had cashed them.  I have now asked for where they were cashed and waiting for the answer. But it stands to reason that both pieces of mail that came from 2 households on separate days had been delivered at the managers office how else would someone get a hold of my separately mailed letters. Also the manager is aware that I receive my rental checks each month.  So when I was researching this find out that in California that each tenant is supposed to have an assigned mail box that locks. I am wondering and have a couple of questions if anyone knows the answer I would appreciate it

1) does this make my landlord responsible for not providing the required secure mail box ?

2) Is the post office liable for delivering multiple residents mail to one mailbox which would be allowing the manager ( not a post office employee) to sort and distribute our mail.?

thank you for any input you can give me.

Pamela Smith