Theft and bad management

I dropped my wife off at work (Checkers Port Elizabeth Lorraine South Africa) where she found that someone stole her lock that was on her locker. When i phoned the manager i was told that my wife must let them know her self about the lock. When she did the Manager (Angelique Volschenk) told that its not their problem thats is not right because lockers is there for the staff to keep there belongings safe not for someone to just take what is not theirs. This is highly unacceptable. Need some answers.