MBD ******

I'm really fuming as I type this. So MTN handed my account over to MBD and so I've been paying MBD so after realizing that the balance is not moving even after the payments I've been making. I called in January asking for a settlement amount and a lady by the name of Dineo sent it to me on the 10tb of January 2020 (the balance the. Was R4744) and I couldn't settle the account in January. I then emailed her couple of times in February to get the latest balance and she never rep**** so I called on Friday 21 February 2020 to get the latest balance and I was told my balance is R4804 and a few cents so on Monday the 24th of February 2020 I paid R4805 and I called today (26 February 2020) asking for a paid up letter and now I'm being told I owe R299. I asked the lady where did that amount come from and she can't explain. She says it's interest so I don't understand how I got charged that much interest between Friday and Monday. So I asked the lady to send me the amount in writing via email so I can pay and get my paid up letter coz I want nothing to do with them anymore and she still hasn't. Tomorrow (27 February 2020) the amount will probably be R400 WHO KNOWS!!! And I'm also worried that I won't get my paid up letter and there will be amounts from no where again.