Telkom unfair billing

To whom it may concern. I have taken out a new Telkom mobile contract on the 26th of February 2018. And was charged the full amount of R600 for 2 days before months end. After phoning Telkom helpline they mentioned that it is standard in there terms and conditions and there is nothing you can do about it. The main problem is that I was not informed about this and had a rude awakening. Not happy with them as this was my last contract that i will take from them