cancellation of Vodacom contract

The cancellations department is not up to standard and need to be addressed. In December / January I phoned to check when my contract is expiring, as I needed to give notice to Not renew contract. I was informed I can do cancellation, so I told them to proceed. Was informed my last installment (debit order) will be deducted on 28 February 2025.I also requested they close my account as I have No intentions of taking anymore contracts.They tried to convince me otherwise, but I made it clear that I'm not interested. So up to here, all was well. My last instalment came off in February 2025 and received no more email statements. On the 15 August 2025, (6 months later) I received a shocking Draft Demand from Vodacom, claiming I now owe them R1808. How is this possible? From all my years, I had many contacts with this company, I've never experienced this shocking service. How can I still owe monies to this company, if they informed me that my contract was expiring and told me I can proceed to have it cancelled and converted to prepaid. If this contract wasn't due to expire, they would've told me to contact them closer to the due date