Call centre not helpful.

I am a telkom mobile subscriber. I have been calling telkom for the past 3 days to blacklist my ****** phone. If I am not made to hold for more than 30 min, I have been send from pillar to post. I spoke to 4 different consultants and they gave me 4 different answers regarding the process. I have been to the store still no assistance. Telkom service is pathetic.