No upgrade fees stated, yet charged

I just did an upgrade on my cellphone contract online with Vodacom. Before finalizing the last step it showed the monthly fee now applicable which was the subs and handset cost. It also had a block to state any other charges to be billed in connection with the upgrade. It showed zero - AS per the website, Connection and Sim fees are for free if an order is placed via the Internet. When I accepted, the order was confirmed and all of the sudden a R150 charge was added to my bill. I phoned the online help desk to be told it is a R150 connection fee. This although it says no charges and even showed zero charge before acceptance of the offer. I was told by the call centre that the free connection is only for new orders and it is stated somewhere in the General Terms and conditions. Strange that I did an upgrade and still the extra charges block showed zero. Surely if you have an applicable charge, you show it in the box you have created for \additional charges"and don't hide it in the wording of your general terms and conditions. This is extremely misleading! What made me do the internet upgrade was the free connection and sim?????"""