Telkom wants to **** me daylight

Last time i Was complaining here with telkom not giving me the service(wifi data) but expecting me to pay. I had a contract with them for the data of 80GB day 80GB night. in April 2022. They decided not to give me data, and they were deducting from my account through debit order. I had to reverse it for as long as i wasn't getting what i was paying for.I reported their matter to ICASA.

Now they are harrasing me,threatening me to pay R1600.00 and something,starting from this very same month. Where have they been all along? And how did they get to that amount coz they have been quite for the whole year and months?Not giving me data(service)not even contacting me? why would I be so keen to pay for something i didnt get serviced for?....

What should I do when I am being harrased by telkom?