Online orders

On Monday the 4th of October, I called the online sales team to assist me with my upgrade for an iPhone 13, I went through the process and I was approved and it was explained to me that this was a preorder, this was well understood, however, I later called Vodacom the following day to get clarity on the contract duration, I was told that the upgrade was made on 36 months, I believe this was not confirmed with me by the agent, I asked that it be changed to 24 months, I was told that the agent who assisted me will get in touch to rectify the matter, it's now day three and I have not been assisted. I don't want 36 months I want 24 please rectify. Thanks