MTN HORRID customer service

This company's customer service is abhorrent. My mother passed away last year. She was a dedicated customer of MTN. When she passed, I contacted MTN and asked what they needed to stop her account as she was deceased. I was told which documentation would be needed. I then proceeded to send the relevant documentation to all the departments. I also handed in hard copies as per requested by their call center. Yet, every month I receive threatening e-mails from nubebt, saying they are going to hand my mom over and blacklist her. I do realize that it will have no impact on her, but it is upsetting to deal with her death and a year later still receive threatening e-mails. Even after I have resent all the documentation to them as well. They just do not respond to any correspondence, but are quick to send their threats. Their customer service is *********** and unhelpful. I will never ever recommend anyone to deal with MTN at all.