Very Upset Line Cancellation a Joke

I am so upset right now. This morning I received a call from debt collector calling on behalf of Telkom wanting over R2000 from me for a line and account that should of been closed and cancelled over a year ago. I have been struggling since last year Jan for this line and account to be closed and every month I ask them and every month they just bill me again. In Dec I was finally helped although I thought I was being helped and told that the line will be cancelled the 15 Jan 2021, I then asked the person about the outstanding amount because I can't pay for something that I did not use and I kept asking them to cancel and nobody came back to me. Now they sent lawyers after me............I need this sorted out. I'm sorry I'm going to pay for something that I asked to be cancelled and closed for more than a year ago and was NOT used.....