Vodacom Bunch Of *******

I was contacted a few weeks ago by a lady from vodacom offering a upgrade on both my numbers at no extra cost whats so ever, (I asked the lady a few times as it did not sounds right) but she assured me that it would not cost a thing and in fact I would be paying less for the 2 numbers, I have now been told that I am being billed for the upgrades, Vodacom needs to fix this and reverse any charges