Vodacom contract is pathetic

I do not even want to give a one star!! I cancelled my contract with Vodacom on the 8th of May 2025. they send me an sms to confirm to convert to pre-paid with effect of 0107/2025. I still have the proof!! Also said that they need 30 days for cancelation period and will take another premium for June. this contract is about 5 years plus old, I did not upgrade. Therefore the phone was already paid, just paid for minutes, data and sms's per month. It just got more expensive and that is why I cancelled. now they keep on calling me for outstanding amount, I would like to know for what. On the 30th of June they took all my remaining minutes and data, which was paid for on the 1st of June. so actually they owe me for taking what already was paid for!! I would not take on a new contract with vodacom nor tell anyone to do so!! Bad bad service!!