Billed for free trial

I tried out dropbox business for a short time. I kept within the dates where I was supposed to cancel my trial before being billed and today I was billed for my few days of trial! I did not budget for this and cannot afford this much money! Dropbox does not seem to have a client center in South Africa that I can contact to get the money back! Please please help me urgently as I need this money to drive this afternoon and it is not my fault! I cancelled within the correct time frame!