Vodacom stole my prepaid Airtime when I kept my number when taking out a contract

I have always been a prepaid customer and maintained a decent balance for calls and data purchases. I recently took out a contract from Vodacom as I needed a new phone. I decided to keep my number as I did not want to go through the hassle to change my number everywhere.

I called Vodacom as to why I was unable to transfer my pre-existing airtime balance that amounted to R625.18. Vodacom said I forfeited it when I kept my number and that the sales consultant in store should have told me. I told them that it was never mentioned, and had I known I would have transferred the airtime beforehand.

This is a serious amount of money that has essentially been ****** from me due to the negligence on the part of the sales consultant at Vodacom Cape Gate.