It is convenient to cancel the subscription and you are in absolute control (in fact, you are the only controller). You can follow the steps from Google Play Website to learn steps to cancel or verify yourself about the status of the subscription.
If you are facing difficulty in using or observing an issue, then please report to us with details so we can provide support. Our global delivery team of engineers is working 24 x 7 in 3 continents to make the app relevant and bug-free.
In case you opened this accidentally but want to know a similar answer for iOS, here is the article.