Free course ****!!

I scrolled through fb and saw an ad for free 4week courses so I decided why not. As I filled in my details, they asked for my banking details to go forward and to start classes I had to do that. I was a bit scared but thought they are well known, why would they even try to rob me? I then have them my banking details and the price of the course was usually R399 but because it was free they had it scratched out and written free on it. I haven't even had time to do any lesson and it's probably exactly 4weeks now and this morning I woke up to a message saying I made a purchase of R399 @ Shaw academy which really ****ed me off! As I've only had a R94 in my bank and needed that money and now I have a minus R300 on my account which means as soon as I receive my salary, they will deduct. I did not want to pay that prices that is why I app**** for the free course! I want my money back because I didn't even use any of the materials or watched any lessons as I've received email as proof that I have done any of the lessons as well. I have 2 kids which I'm supporting, don't have a R400 to give away for free!!!!!