********* billing, unprofessional, no resolution

On the 5th of January 2016 I called to find out what my balance is on my account, I was informed my settlement balance was R5,067.60 and I should settle before the 7th otherwise my offer lapses. I received the email with the settlement amount, I paid the amount and called the following day to find out if the amount reflects, it did not as they couldn't identify my account even though I used the reference given on the settlement letter. Payment was then allocated to my account. I heard/received nothing back. I called to get confirmation my account is settled and was informed I have an amount of over R1000 still owing on my account. They said I should email the settlement letter so they can investigate, I did and heard nothing back. I called again and nothing had been done, I was requested to send the settlement letter again. Again I heard nothing back, so I called and was informed that they will clear my account and I should receive confirmation within a day or two. I received no confirmation again and called again, it's the same story, no one can help me, it's not their department. What do I do now? I call, I get no help, I send an email, I get no help.