Telkom Contract "Cancelled"

in 2018 I cancelled my contract because I was due for an upgrade so I cancelled because I'd been having problems with your billing. 2018 same year you carried on with the weird billing, I wen to Telkom at Nicoleway in Brynston JHB and the guy spent an hour with the call centre trying to figure out what was going on. I then decided I'd stop paying. Then I git calls and emails from Debt In saying Telkom had handed my account over to them. I refused to pay because I didn't know why I had to pay so much when I was only supposed to pay R60 or something the last month of my contract.

Then in 2020 (this year I finally decided to pay Telkom/Debt In off so that I could clear my name and start afresh. I have paid nearly over 5k to Debit In because they charged me for everything including missed phone calls with them.

on the 25th of July I paid my last installment with Debit In which was R2845 (something around there). I was told that once I have finished I'd get a letter telling me that I am done paying Telkom. I received thus letter and I was over the moon.

This morning do I not get an invoice from TELKOM saying I owe them 1700 and something. This is extremely unfair because I have paid my dues and shouldn't be receiving such.