Be careful for Debt-In Courtesy Calls you Pay R20 for every call they made to you

I got late with payments on my 8ta account and they handed me over to Debt-In based in KwaZulu Natal. I made an arrangement that I will pay on the 25th of every month which I do. On the 21 of every month, I got a call from Dept-In and pay for that call R20. That is after I made the arrangement with them. I try to get Telkom Legal Departments number but can't find it on the internet. Is it possible to address Debt-In and the Legal Department of Telkom? I paid almost a thousand rand on these courtesy calls. Is there someone who can help me to get that money back?