If you wish to cancel your subscription and get a refund,

For IOS:

Cancel: do so in AppStore -> Subscription on your device.

Refund: https://support.apple.com/en-us/HT204084

 

For Android:

Cancel: https://support.google.com/googleplay/answer/7018481?hl=en&co=GENIE.Platform%3DAndroid

Redund: https://support.google.com/googleplay/answer/2479637?sjid=1132056180235917896-NA#policy