I mistakenly purchase this app on my phone " Don`t touch my phone" how can I cancel it?\

Hello messanvi,

Unfortunately there is no way to cancel purchases on the App Store. You can contact Apple Support here to try and request a refund. As long as you don't do this too many times Apple may give you a refund however they are by no means obliged to from what I understand.

I hope this helps,

Henry G