Misleading offer

I was called some months back by a 3rd party called Mondo and offered a lower monthly fee with more minutes as I had been identified "as a valued Vodacom customer" I asked several times whether this would affect me being able to upgrade my device when I wanted to and the sales lady assured me it would not so, I agreed to it. The big saving was all of R53/month. I am now wanting to upgrade and see that my upgrade date, which was around August last year has now been moved to July 2021. Have called Vodacom directly to complain and they are going to listen to the recording and get back to me in 3 - 7 days!