A big ERROR / MISANDERSTOOD !!!

Hello, I am very very worried and I hope someone could help me. First, I am French so excuse me if I don't speak correctly English.

I  pay every month for Creative cloud and  I wanted to try Adobe stock for 1 month as proposed. When I saw 10 free photos for trying, I said "wonderful !"

So I did load 3 photos and it was written "still 7 photos" I did load one more and I don't know why this one appeared as a purchase ??????

I am very confused and the worst is the price of this picture : 499 € !!!!! and I didn't want to buy this photo

I hope it is possible to cancel this purchase?!

THANK YOU VERY MUCH FOR YOUR HELP !!!!