Ackermans played a role in hecking my son's phone.

A man has suddenly taken over my son's mobile number even WhatsApp calls. Meaning that he will also receive personal sms with private details that are meant to be received by my son. I called my son on WhatsApp and this man answered the call and says he bought a new phone from Ackermans in Diepsloot yesterday around 17:00pm and he was given this number. Does Ackermans even consider security measures