Unhappy Customer

I am so disappointed in how Vodacom is doing business, I took a 36 months contract just 2022, I called to cancel in June. I was notified I will not be charged for cancellation fee as I agreed to pay till August 2025. But now I have been handed over because I reversed 600 that they debited without my consent in September 2025, what was that about ? Now I can’t even get hold of the cancellation department to enquire about this because my number is now prepaid. How do I resolved this ?