Telkom LTE charging for unused services

Took out 20GB LTE for my son to be debited to my account. Got the special as it was 50% off at R250 plus VAT

As he works from home, the bundle would run out and I would manually top with my credit card on the Telkom website.

Telkom have been charging me an extra R1000+ or more for data he has never used for months now. I called to have it sorted out but I'm still getting debited massive amounts!