Blacklisted for cancelled contract

I am not happy with what you did to me, I opened a home wi-fi contract with Mondo MTN Telephonically, out of all the things the agent said, I clearly heard her saying its uninterrupted network without hesitation I needed it so I agreed. it came on the 1 June 2022 and it worked for 2weeks the rest of the month I couldn't use it, it was glitch after glitch until month end of June same problem. I decided to disconnect it and ask a cancellation on the 7th July, on the 12th Email came through that said Contract has been cancelled with immediate effect, I asked for cancellation letter to date i haven't received it, 2weeks (13 October 2022) I found that I have been Blacklisted.