Mondo/MTN Disgusting customer service

I had someone from Mondo phone me a couple months back, sold me this great contract for R150 pm when I got the SIM card the contract was completely different to what I agreed to. I cancelled it and was advised cancellation was completed 26/03/2021 I have just been debited R265 for the 3rd month in a row. This is not even what I agreed to!!!! Keep being told via email this has been escalated and I will receive feedback, I have received no feedback at all. I managed to get through to Mondo, they confirmed it has been cancelled but mtn is responsible for the credit? The contact has been cancelled so how is this going off of my account?! I can’t keep reversing the debit as it will affect my credit score. This is ridiculous.