Contract Upgrade Fiasco

I was contacted on 07 June 2023 by a customer care agent to assist me to upgrade my contract as I was due for an upgrade since 13 May 2023. I didn't want a new device as I was happy with the device I had so I only wanted to do a sim only upgrade i.e. only renew the data/SMS portion of my contract. I was given an order number and told my contract was upgraded. I was also told I'll only pay R220 a month going forward. 02 July 2023 MTN debited my account with my previous monthly amount, R708. I thought that because my contract was upgraded in the middle of the month I would still be charged my old amount, but on 02 August 2023 my account was AGAIN debited with R708. MTN, please fix this issue, and refund the money I paid extra for the last 2 months because my contract wasn't upgraded like I was told it was. Absolutely appalling service from MTN, and I've been a loyal customer since 2012.