Vodacom contract settled in full, contract expired, number recycled and I am still being invoiced for a recycled number?

Contract cancelled 30 September 2021. Settlement amount paid in full 30 August 2021. Confirmation received that the account is settled in full - also reflecting on August Statement. Cell number was recycled as of November 2021. 11 May 2022, I received an invoice for an amount outstanding for the month of May 2022. If a consumer fails to make a payment, the consumer is reported to the credit bureau. What happens when the service provider bully’s an “old” customer into renewing a contract that is paid in full, cell number recycled and upgrade on the contract not signed for? This is exploitation.