******* business practices

I had a fibre account that I then cancelled with cell c after 7/8 months. The person who sold it to me said this was a month-to-month contract and I can cancel at anytime. Nowhere in the process was I told that if i cancelled before 24 months i was liable for the payment of the hardware. My understanding was that everything was free, those were the guys exact words. I now find out I am liable for almost R1800 which they've debited on my account. I've asked for over 3 months now to have proof that I was aware of this and where I signed for this and they are not getting back to me with the proof. This is ******* surely.