Poor customer service

I contacted customer service for assistance with blacklisting my device and couldn't get assisted. I spoke to the 1st Agent by the name of Thabisa Makhala who promised to call me back as encountering system issues, she never did. I had to callback and spoke to Onami and was told I couldn't blacklist my number and phone and told to go the store as she couldn't assist. I then asked to speak to a manager, which I was deprived that right and the phone hung up on me. What a pathetic service. I'm highly disappointed about the service.