MTN/Mondo

I'm writing this hoping there's someone who work at MTN who care about customer, i have been a customer at MTN for many years. I have 2 numbers with them and upgraded my second line in September 2021, the phone was delivered and it was faulty, i returned the phone within cooling period it took a more than a month to confirm they have received the phone when it only took them few days to deliver. To date i'm still been charged for the phone i do not have, from October 2021 to date they are still cancelling reversing the debit on my account. Every time i call i'm been referred from pillar to post. Mtn mondo 99 % of the time their they are offline and manager will call and they never call I have requested for my account to be corrected so i settle my account, they open query and close it without even calling me back and then block my line. I call 135 and they refer me MTN mondo, i dont care who mondo is i have a contract with MTN, SORT IT OUT NOW BA***