Vodacom rip-off

I upgraded to an iPhone 8 on 16 July, at Cresta 4U store. I was advised, by a consultant I don't care to mention, that I would only start paying for the new handset at the end of my current contract.

From 16 July, the sim card was not activated (not making calls or using the internet) and was told by Vodacom call centre agents that my upgrade is still pending and thus my line is not live. On July 27, I went back to the store and they were able to get it activated for me. Now I could make calls and access the internet.

Yesterday, I try to make a call and realize my usual data-airtime-SMSs were not loaded as expected on the 1st of August. I go online (using WiFi) and discover that my bill is larger than expected.

When I called this morning they advised me that because I upgraded, I am to pay for both the old and the new handsets immediately, and they are billing me other additional costs. The cost of this upgrade has blown up to an amount I can not afford. I do not have the money to pay for these extra costs. My previous upgrade (2 years ago) went smoothly, but this time...

Seeing that my upgrade became active only on 27 August (despite having the phone since 11 August, it is not my problem when you activated it), I am still within the 14-day return window. Please be aware that I am returning the phone and canceling the upgrade tomorrow, day 14. I did not sign up for this.