Vodacom Billing Issue

My name is Matsie, i called Vodacom on the 18th March 2025 to downgrade on my Wifi from R829 to R499 and the person i spoke to said the downgrade will take 5 days and i will be charged a pro rata which the amount should me less however to my suprise Vodacom debited the R829. I then called again on the 2nd April , spoke to the billing department and the guy said he will call me back as he had system issues but he didn't call me. i called vodacom for the 3rd time on the 7th April and was advised that the downgrade wasn't done and they will process again and it take 5 days again and i will only pay for the 7 days on the old plan and going forward the R499 . Now again this morning they debited R829 , not sure why am i still paying this amount even after the downgrade. This is not the first time having billing issues on this account. Vodacom's customer service is poor and its irritating cause i told them that i cant afford the R829 plan and they should downgrade. I will be disputing the debit order until they debit the correct amount.