Telkom threatens with letter of demand when they failed to setup debit order.

I cancelled my broadband services with telkom literally a year ago. I then continued to get billed, then i had debt collectors call me, Telkom then refunded that billings and said i still had to pay an amount of R2250. I spoke to Abulele Mbie (A) ********** I asked if i could pay the amount in installments to which she contacted the billing manager who set out a stipulation of 40% upfront and the balance paid over 2 months. I agreed and have heard nothing back from anyone at Telkom. I now received a letter of demand threatening legal action and blacklisting.