I want get back my money as I don’t want purchase that app?

To cancel the subscription.

Purchases - View, change, or cancel your subscriptions.        

Purchases - Subscriptions not billed through Apple  

Link to contact Apple Support at the end of the article.

Purchases - the subscription that you want to cancel is not listed   

Normally, all sales are considered final, but you can ask for a refund.

If you have received a confirmation email, click the Report a problem link at the bottom.

Purchases problem.      

How long refunds from the App Store or other Apple services take.