Avis Payed too much

I buyed a perfume from 19,90€
But I payed 29,90€ for it.
I haven't seen on the ticket that it was 10 euro less. Because the ticket was packed in the sac with the parfume. And it was forbidden to open the sac. My advise before you buy something in this shop. Make sure you check your ticket and open your sack to check if you payed too much. There is no e-mail. That's why I write it in a review. Please contact me, I want my money back. Thanks!