Unknown charge

I need help. I canceled this ride cause it was taking too long to arrive. This person saw that its better to drive around with my card and then extended my destination. My card was debited R100. I didn't take that ride and was asleep at the time. From where I was to that destination is R20. I need an explanation of how my account ended up being debited a R100 after I canceled the trip. I want my money!!!!