Shocking service leading to debt in my name.

I contacted Vodacom and asked to pay up all my Vodacom contracts in January 2023, which I was advised on and I believed I was squared up with them. BUT then I received notification from Hammond Pole Attorneys on 9 May regarding Vodacom arrears payment. Between January and May I had received absolutely no communication from Vodacom notifying me that I was incurring debt. I paid up in full to the attorneys, because I am a person who does not like to be in debt to anyone even though I felt this was unfair due to Vodacom not doing their job properly when I paid up my contracts. Yet, today, I received a Final Demand from Vodacom saying I am in arrears demanding payment. Finally, at least direct communication from them, however it means 6 months later Hammond Pole has not settled the arrears account with Vodacom and I am still incurring further debt in my name! Shocking service all round.