Vodacom theft of funds

I cancelled my contract with Vodacom as prescribed on 30 June 2025, my contract's last payment was supposed to be debited on 1 July. I received confirmation that the contract was cancelled, ending 31 July 2025. On 1 Aug my debit order went through and the cancelled contract funds were again debited. When I enquired Vodacom said that 1 August was the last debit order for that contract. I paid one month extra. They dont seem to agree with me.