The agent threatened me and she was so rude no sense of humanity

An agent named fiona mahomed from select online credit recovery called me regarding my cellc account this account has been listed as paid up on my itc because its prescribed, they keep calling and sending messages and harassing me. So I called them back on the 27 January 2018 and spoke to fiona I explained that the account on my itc shows paid up with no balance ,in all this years cellc never contacted me but suddenly they are calling me she then transfered me to a lady named sivani who was so rude to me she threatened me and spoke to me so rudely after I explained that I have my itc report with me and it clearly states paid up , she than got very aggressive and told me to email it to her I dont understand why because an itc report is private , but I still emailed it because I was tired of they harassments, she then told me she is going to list me even though I sent her the report. They still sent me a message stating they are going to send a sheriff to my house to attach my assets and I clearly no thats against my south african consumer rights ...please help me deal with this