Poor service

I cancelled my contract in February, I was tired of the poor service and slow network. 400 was debited from my account even though my premium was hundred and something. I did not call them as I assumed since it was my last month maybe that's how its supposed to be. A month later I got an email from nu debt, they told me that I have been handed over, I told them to get someone from Neotel because from my knowledge I owe them nothing, nu debt responded few weeks later to say they have closed the matter and they have handed it back to neotel. No one from neotel contacted me but they debited 119. I phoned them to ask them, I was told a long story I just say fine, I my account up to date now, I was told yeah its closed. Yesterday I got an sms from Neotel to say my account has been handed to nu debt I owe 100. I want whoever from neotel to listen to my calls, im sure they can trace that with my account no. I have been told 2 or 3 times that my account is closed but neotel still continues to debit and hand my account over. Its tiring and sickening. Am I being punished for cancelling my contract?