VODACOM HIDDEN TERMS ?

In November 2018 I called the Vodacom hotline inquiring about when I might be able to cancel my data / wifi contract. The premium was just to high for me to afford at this time. No they said - I can only cancel in February. Not a problem. In February I went to a shop to have it cancelled in time. There the lady asked me whether she could borrow my phone? Because the Vodacom shop had no working telephones? With that I was still fine - unfortunately my battery had died and she borrowed a phone from someone in the shop. After holding on for something like 45 minutes an operator answered. I answered all his questions and after telling him 6 times that I wanted to cancel the contract and "NO I DO NOT WANT TO UPGRADE". The contract was cancelled - or so I thought. On 5 May which was supposed to be my last installment - they deducted R 986.89 which is R403.51 to MUCH!!

I then called accounts inquiring about the payment. Their answer - I was supposed to know the last payment would be this much. Discount on deals (like in the booklets) only count for 22 to 23 months of a contract. the 24th months' payment is the full amount of what it is supposed to be (2 years ago)? Isn't the shop of the operator supposed to tell people about that?

I went to another shop and they told me that the contract was only cancelled 9 March ?? WHY ???

I budget for everything now I've lost more than R400 and their answer is just sorry they can't so anything about it?