VERY poor service from MTN after 15 years of loyal contribution

Mr Nel, a client of mine, has the above account for almost 15 years. Amazingly, since August this year, Mr Nel has been trying to obtain information from MTN, after their Legal department called him, advising him that the account is in arrears with a substantial amount (quite arrogant, as I understand from him). Simple request. Could you kindly provide a statement? From 13th May 2019, almost 2 weeks ago, we have been in contact with MTN, escalating this query from one department to the other. Now, once again, a simple question - provide the proof of payment that was sent to your ********** dept on 12.11.2018. They read this, as can be seen from the read report, rep**** and provided a time limit of 48 hours. After the lapsed time, I called and e-mailed the person whom is responsible for MTN. Then you get an automated response from her e-mail address. Conveniently, out of the office, and will attend to the query when back. No time span here! Ok, MTN : Here is the deal. Contact me, or this same complaint will be loaded onto your face book page.