Getting Billed post account cancellation

I am very dissappointed with Vodacom to say the least, my contract was on a month to month, I called in to cancel with immediate effect on 22 May 2025. After the Agent gave me a hassle and and even became hostile before they eventually agreed to cancel, I got billed end of May and now end of June Im getting billed again. I need this resolved asap, and my money refunded.