Frustrated by MTN agents incompetency and lack of empathy

My phone was ****** and I have been trying over an hour to call ask MTN to blacklist my phone. ******** will have access to my personal data including whatsapp and banking information. I am in Johannesburg at the moment and have asked my child to phone them and they refuse to blacklist the phone and they want me to call MTN tomorrow. If my phone is ****** and I do not have access to a phone how do they expect to call them.

Can MTN try to show empathy and just block the phone.