Subscription and payments are handled through Apple. Only Apple can process refunds for purchases made through an Apple iTunes account.
We also recommend that you cancel your subscription to prevent being charged further on the next cycle. To do so, you'll just need to turn off auto-renew within your phone's iTunes account settings. You can follow the instructions on the Apple site.
If you are facing difficulty in using or observing an issue, then please share the issue with details to get help. Our global delivery team of engineers is working round the clock to make the app relevant and bug-free.