Over-Charged despite canceling and downgrading contract

Since Septenber 2025 I've had issues with vodacom. I want to cancel my Fibre contract with vodacom and the agent presented that as a loyal custumer I would be entitled to a reduction in my contract... When I fact all she offered was a lower plan with an equivalent lower package.. Nonetheless I agreed... Initial plan about R850, reduced plan about R460. Every month since then they have, like clock work deducted the R850ish amount from my account. Every month I have had had to call them and explain the whole situation to another agent that always starts by saying that my contract is R850ish amount. I have spent hours on the phone and 3vwntually insisted that they pay out the differences owed to me. I made it clear to the agent that I want the money reimbursed. And guess what... They credited my account. At the end if November while calling them about the reimbur*****t. I canceled my Fibre account with them. Low and behold yesterday and amount R772ish was deducted... Instead of the R460. Pathetic dishonest service... Costing me lots of time and money calling them. As little it might be to you, please pay me what you owe me. And don't deduct any more money from account. I finally sent them an official email on 29 November to cancel my contract with them