Insecure Self Service

I have been a victim of DTSV's lack of security on their self service whatsapp platform. Someone managed to reactivate my old DSTV account which was terminated 2 years ago, registered their own decoder and smart card, and billed me using direct debit. They didn't have access to my ID number, phone, or email address. DSTV kindly told me that there is nothing that they can do, as it was reactivated on self service, so it not their fault, so i'm out of pocket of nearly R1,800