Call centre and over charging

On 29th September my iPhone was ****** and then I reported to Telkom on the 1st October, they advised me that the person using the phone has increased the permanent spend limit of R1 to R500. they blocked the simcard after R103 was spent. now my question is, how permanent is this spend limit if someone can change it? Now I called the call centre and Irene after I requested the manager told me that the manager will say the same thing and she put me on hold ever since as i'm still on hold for 1 hour 15.