Contract upgrades

I took a contract with Vodacom back in December 2021 and the agent who was assisting me I told her I need 24 months on both contract it only came to my surprise last week when someone from Vodacom contacted me to say m due for an upgrade but on one sim only not both phones while I told the lady that I can not have a phone on a 36months contract I need it in a 24 months on one sim she did 24months and other sin she did it for 36months and I did complain to Vodacom about this issue and on the 12/11/23 received an Sms that my complaint was received and they looking in to it should receive feedback in the next 48 to 72 hours bow it's 120hours still waiting no update nothing I am so disappointed with Vodacom whenever I phone call centre I am being sent from pillar to post