I’ve been charged $2.99 every week and I didn’t even know it

I’ve down loaded the app just to try it out. I didn’t like it after few try so I’ve deleted it. This was a year and half ago
My husband just told me that his credit card has been charged $2.99 every month by iTunes and came to find out it was this app.....lord! This been going on a year and a half. Yes. It’s our fault not to investigate this charge early but I didn’t signed on for the subscription! So how?

Violet1916 about Recolor - Coloring Book, v4.1.2