Theft at store

I accidently left my wallet together with my things at clothing junction pinecrest and I was ****** R600 was ****** from my wallet i had a balance of R1200 and when i checked it R600. The guy who is working there Nkosi Tembe kept laughing at me like I was fool. Promised that they will check the cctv footage and get back to me. If they do not I'm opening a case theft how can they still from customers.