Pretending to be part of Telkom

An agent of Mobile Talk contacted me to upgrade to LTE system, which is super fast and mobile. I was immediately interested, seeing that they knew all my personal details and lead me to believe they are part of Telkom. After I agreed, I received a confirmation email and immediately became suspicious, as there was no Telkom affiliation evident. I don't know how they had so much private information, including my identity number, in their data base. It is very scary. I have cancelled the order. Just hope they will not debit my bank account.