Can i get the money that i put in my app store from a gift card back into my bank account?

My grandpa wanted me to look up some spy software apps to where he could see my grandmas texts and locations. Without her knowing on his phone. After seeing this app called “mspy” i was doing more research on it and the app really doesn’t work on iPhone but before i knew that he gave me 40$ cash and i went and got some gift cards and put it on his account to pay for the subscription. But now I’ve decided we aren’t going to do that and we haven’t spent money yet. Can I somehow get that money back into a bank account so I can get him his money back in cash?

-Sebastian

[Personal Information Edited by Moderator]