Vodacom ****!!!!

On Friday 28.02.2020 received a call from a lady Minienhle telling me that Vodacom would like to offer me 25% discount on my monthly data spent and I agreed, the next thing they put in my account 100 GB and tell me I must pay additional R1874.90 hence I believe it was misrepresented ,I did not agree to receiving additional 100GB ,can Vodacom please remove that on my account as I have not even used it ,