Unresolved query since 2017 and bad customer service

I have an unresolved query since 2017. I have called their call centre in june/2019 asking them to clear my account because i have paid in 2017, I was told to wait for 21 days and i did. I then called after the 21 days and i was told that i have to wait for another 21 days, i was patient and i did, i called again and i was told to wait for another 21 days, i told the consultant by the name of Zinhle that i can't, i asked to speak to the supervisor but she didn't come to the phone. I was told that she is going to call me and sent an email, but I'm still waiting until now ever since June/2019. The supervisor is Ntombi. I am so disappointed in their service after being so patient with them for so long.