Patronised Client

I have a serious issue with this debt collection company(ITCBA). In fact i'm patronised by the system and how they handle things in this company. The lady I spoke to over the phone was just so rude and hung up the phone on me. I mean my Avon account was been handed over to the ICTBA. I had a debt of R795.08. End of March 2021 I paid R100.00. 14 April 2021 I paid R20 the last money I had to decrease the debt. On 18 April I paid R205.08. Instead of my balance being R470.00 the amount went up by R8.15. How am I supposed to settle the amount if I have to pay for the calls they make and sms's they send. How is that my problem? All I want is to settle the costs that's it instead of having to pay for telephone bills which the company has to settle. I'm so upset. The worst part of it all is the email address isn't working at all